List of Unique Entities in Valve Source Games

Lists of entities that exist only in the given game and no other
== Counter-Strike: Source ==
No unique
== Half-Life: Source ==
No unique
== Half-Life 2 ==
No unique
== Half-Life 2: Deathmatch ==
basehl2mpcombatweapon
hl2mp_gamerules
hl2mp_ragdoll
info_player_combine
info_player_rebel
npc_satchel
npc_tripmine
weapon_hl2mp_base
weapon_slam
== Day of Defeat: Source ==
base_rocket
dod_ammo_box
dod_bomb_dispenser
dod_bomb_dispenser_icon
dod_bomb_target
dod_capture_area
dod_control_point
dod_control_point_master
dod_gamerules
dod_location
dod_objective_resource
dod_player_manager
dod_ragdoll
dod_round_timer
dod_scoring
dod_team_allies
dod_team_axis
dod_team_manager
dod_viewmodel
env_grenadetrail
func_team_wall
func_teamblocker
grenade_frag_ger
grenade_frag_us
grenade_riflegren_ger
grenade_riflegren_us
grenade_smoke
grenade_smoke_ger
grenade_smoke_us
info_doddetect
info_player_allies
info_player_axis
rocket_bazooka
rocket_pschreck
weapon_30cal
weapon_amerknife
weapon_bar
weapon_basebomb
weapon_basedodgrenade
weapon_bazooka
weapon_c96
weapon_colt
weapon_dod_base
weapon_dod_base_gun
weapon_dod_base_melee
weapon_dodbaserpg
weapon_frag_ger
weapon_frag_ger_live
weapon_frag_us
weapon_frag_us_live
weapon_garand
weapon_k98
weapon_k98_scoped
weapon_m1carbine
weapon_mg42
weapon_mp40
weapon_mp44
weapon_p38
weapon_pschreck
weapon_riflegren_ger
weapon_riflegren_ger_live
weapon_riflegren_us
weapon_riflegren_us_live
weapon_smoke_ger
weapon_smoke_us
weapon_spade
weapon_spring
weapon_thompson
== Half-Life 2: Lost Coast ==
weapon_oldmanharpoon
== Half-Life Deathmatch: Source ==
hl1mp_gamerules
== Half-Life 2: Episode One ==
No unique
== Half-Life 2: Episode Two ==
No unique
== Portal ==
func_liquidportal
npc_grenade_hopwire
npc_portal_turret_ground
updateitem1
updateitem2
vortex_controller
weapon_hopwire
== Team Fortress 2 ==
_ballplayertoucher
archer_proxy
base_boss
bot_action_point
bot_controller
bot_generator
bot_hint_engineer_nest
bot_hint_sentrygun
bot_hint_teleporter_exit
bot_npc_archer
bot_npc_decoy
bot_proxy
bot_roster
dispenser_touch_trigger
entity_bird
entity_carrier
entity_croc
entity_medigun_shield
entity_revive_marker
entity_rocket
entity_saucer
entity_sign
entity_soldier_statue
entity_spawn_manager
entity_spawn_point
env_sniperdot
eyeball_boss
filter_activator_tfteam
filter_tf_bot_has_tag
filter_tf_class
filter_tf_condition
filter_tf_damaged_by_weapon_in_slot
filter_tf_player_can_cap
func_achievement
func_capturezone
func_changeclass
func_croc
func_flag_alert
func_flagdetectionzone
func_forcefield
func_nobuild
func_nogrenades
func_passtime_goal
func_passtime_goalie_zone
func_passtime_no_ball_zone
func_powerupvolume
func_regenerate
func_respawnflag
func_respawnroom
func_respawnroomvisualizer
func_suggested_build
func_tfbot_hint
func_upgradestation
game_forcerespawn
game_intro_viewpoint
game_round_win
game_text_tf
ghost
halloween_fortune_teller
halloween_souls_pack
halloween_zapper
headless_hatman
hightower_teleport_vortex
info_observer_point
info_passtime_ball_spawn
info_populator
info_powerup_spawn
item_ammopack_full
item_ammopack_medium
item_ammopack_small
item_armor
item_bonuspack
item_currencypack_custom
item_currencypack_large
item_currencypack_medium
item_currencypack_small
item_healthammokit
item_healthkit_full
item_healthkit_medium
item_healthkit_small
item_powerup_crit
item_powerup_rune
item_powerup_rune_temp
item_powerup_uber
item_teamflag
item_teamflag_return_icon
mapobj_cart_dispenser
merasmus
merasmus_dancer
monster_resource
obj_attachment_sapper
obj_dispenser
obj_sentrygun
obj_teleporter
passtime_ball
passtime_logic
pd_dispenser
point_intermission
point_populator_interface
populator_internal_spawn_point
prop_soccer_ball
rd_robot_dispenser
tank_boss
tank_destruction
teleport_vortex
tf_ammo_pack
tf_base_minigame
tf_bonus_duck_pickup
tf_bot
tf_dropped_weapon
tf_flame
tf_flame_manager
tf_gamerules
tf_gas_manager
tf_generic_bomb
tf_glow
tf_halloween_gift_pickup
tf_halloween_gift_spawn_location
tf_halloween_minigame
tf_halloween_minigame_falling_platforms
tf_halloween_pickup
tf_logic_arena
tf_logic_bonusround
tf_logic_competitive
tf_logic_cp_timer
tf_logic_holiday
tf_logic_hybrid_ctf_cp
tf_logic_koth
tf_logic_mann_vs_machine
tf_logic_mannpower
tf_logic_medieval
tf_logic_minigames
tf_logic_multiple_escort
tf_logic_on_holiday
tf_logic_player_destruction
tf_logic_robot_destruction
tf_logic_training_mode
tf_mann_vs_machine_stats
tf_merasmus_trick_or_treat_prop
tf_objective_resource
tf_pda_expansion_dispenser
tf_pda_expansion_teleporter
tf_player_manager
tf_point_nav_interface
tf_point_weapon_mimic
tf_powerup_bottle
tf_projectile_arrow
tf_projectile_ball_ornament
tf_projectile_balloffire
tf_projectile_cleaver
tf_projectile_energy_ball
tf_projectile_energy_ring
tf_projectile_flare
tf_projectile_grapplinghook
tf_projectile_healing_bolt
tf_projectile_jar
tf_projectile_jar_gas
tf_projectile_jar_milk
tf_projectile_lightningorb
tf_projectile_mechanicalarmorb
tf_projectile_pipe
tf_projectile_pipe_remote
tf_projectile_rocket
tf_projectile_sentryrocket
tf_projectile_spellbats
tf_projectile_spellfireball
tf_projectile_spellkartbats
tf_projectile_spellkartorb
tf_projectile_spellmeteorshower
tf_projectile_spellmirv
tf_projectile_spellpumpkin
tf_projectile_spellspawnboss
tf_projectile_spellspawnhorde
tf_projectile_spellspawnzombie
tf_projectile_spelltransposeteleport
tf_projectile_stun_ball
tf_projectile_syringe
tf_projectile_throwable
tf_projectile_throwable_breadmonster
tf_projectile_throwable_brick
tf_projectile_throwable_repel
tf_pumpkin_bomb
tf_ragdoll
tf_robot_destruction_robot
tf_robot_destruction_robot_spawn
tf_robot_destruction_spawn_group
tf_spawner
tf_spell_meteorshowerspawner
tf_spell_pickup
tf_target_dummy
tf_taunt_prop
tf_team
tf_teleport_location
tf_viewmodel
tf_weapon_base
tf_weapon_bat
tf_weapon_bat_fish
tf_weapon_bat_giftwrap
tf_weapon_bat_wood
tf_weapon_bonesaw
tf_weapon_bottle
tf_weapon_breakable_sign
tf_weapon_buff_item
tf_weapon_builder
tf_weapon_cannon
tf_weapon_charged_smg
tf_weapon_cleaver
tf_weapon_club
tf_weapon_compound_bow
tf_weapon_crossbow
tf_weapon_drg_pomson
tf_weapon_fireaxe
tf_weapon_fists
tf_weapon_flamethrower
tf_weapon_flaregun
tf_weapon_flaregun_revenge
tf_weapon_grapplinghook
tf_weapon_grenadelauncher
tf_weapon_handgun_scout_primary
tf_weapon_handgun_scout_secondary
tf_weapon_invis
tf_weapon_jar
tf_weapon_jar_gas
tf_weapon_jar_milk
tf_weapon_katana
tf_weapon_knife
tf_weapon_laser_pointer
tf_weapon_lunchbox
tf_weapon_lunchbox_drink
tf_weapon_mechanical_arm
tf_weapon_medigun
tf_weapon_minigun
tf_weapon_parachute
tf_weapon_parachute_primary
tf_weapon_parachute_secondary
tf_weapon_particle_cannon
tf_weapon_passtime_gun
tf_weapon_pda_engineer_build
tf_weapon_pda_engineer_destroy
tf_weapon_pda_spy
tf_weapon_pep_brawler_blaster
tf_weapon_pipebomblauncher
tf_weapon_pistol
tf_weapon_pistol_scout
tf_weapon_raygun
tf_weapon_revolver
tf_weapon_robot_arm
tf_weapon_rocketlauncher
tf_weapon_rocketlauncher_airstrike
tf_weapon_rocketlauncher_directhit
tf_weapon_rocketlauncher_fireball
tf_weapon_rocketpack
tf_weapon_sapper
tf_weapon_scattergun
tf_weapon_sentry_revenge
tf_weapon_shotgun_building_rescue
tf_weapon_shotgun_hwg
tf_weapon_shotgun_primary
tf_weapon_shotgun_pyro
tf_weapon_shotgun_soldier
tf_weapon_shovel
tf_weapon_slap
tf_weapon_smg
tf_weapon_sniperrifle
tf_weapon_sniperrifle_classic
tf_weapon_sniperrifle_decap
tf_weapon_soda_popper
tf_weapon_spellbook
tf_weapon_stickbomb
tf_weapon_sword
tf_weapon_syringegun_medic
tf_weapon_wrench
tf_weaponbase_grenade_proj
tf_weaponbase_melee
tf_weaponbase_merasmus_grenade
tf_wearable
tf_wearable_campaign_item
tf_wearable_demoshield
tf_wearable_levelable_item
tf_wearable_razorback
tf_wearable_robot_arm
tf_wearable_vm
tf_zombie
tf_zombie_spawner
training_annotation
training_prop_dynamic
trigger_add_or_remove_tf_player_attributes
trigger_add_tf_player_condition
trigger_bot_tag
trigger_ignite
trigger_ignite_arrows
trigger_particle
trigger_passtime_ball
trigger_player_respawn_override
trigger_rd_vault_trigger
trigger_remove_tf_player_condition
trigger_stun
trigger_timer_door
wheel_of_doom
wheel_of_doom_spiral
== Left 4 Dead ==
func_fire_extinguisher
func_nav_stairs_toggle
func_spawn_volume
info_solo_changelevel
prop_glowing_object
== Left 4 Dead 2 ==
ability_charge
ability_leap
ability_selfdestruct
ability_spit
ambient_music
charger
env_airstrike_indoors
env_airstrike_outdoors
env_physics_blocker
filter_health
filter_melee_damage
func_block_charge
func_extinguisher
func_nav_connection_blocker
func_playerghostinfected_clip
func_timescale
game_scavenge_progress_display
grenade_launcher_projectile
info_ambient_mob_end
info_ambient_mob_start
info_item_position
info_l4d1_survivor_spawn
info_particle_target
info_zombie_border
insect_swarm
jockey
logic_director_query
logic_game_event
point_nav_attribute_region
point_prop_use_target
point_script_use_target
prop_minigun_l4d1
prop_physics2
prop_wall_breakable
script_clip_vphysics
script_func_button
script_nav_attribute_region
script_nav_blocker
script_trigger_hurt
script_trigger_multiple
script_trigger_once
script_trigger_push
scripted_item_drop
sound_mix_layer
spitter
spitter_projectile
survivor_death_model
trigger_active_weapon_detect
trigger_callback
trigger_upgrade_laser_sight
upgrade_ammo_explosive
upgrade_ammo_incendiary
upgrade_laser_sight
upgrade_spawn
vomitjar_projectile
weapon_adrenaline
weapon_adrenaline_spawn
weapon_chainsaw
weapon_chainsaw_spawn
weapon_charger_claw
weapon_cola_bottles
weapon_defibrillator
weapon_defibrillator_spawn
weapon_fireworkcrate
weapon_gascan_spawn
weapon_gnome
weapon_grenade_launcher
weapon_grenade_launcher_spawn
weapon_item_spawn
weapon_jockey_claw
weapon_melee_spawn
weapon_pistol_magnum
weapon_pistol_magnum_spawn
weapon_rifle_ak47
weapon_rifle_ak47_spawn
weapon_rifle_desert
weapon_rifle_desert_spawn
weapon_rifle_m60
weapon_rifle_m60_spawn
weapon_rifle_sg552
weapon_rifle_sg552_spawn
weapon_scavenge_item_spawn
weapon_shotgun_chrome
weapon_shotgun_chrome_spawn
weapon_shotgun_spas
weapon_shotgun_spas_spawn
weapon_smg_mp5
weapon_smg_mp5_spawn
weapon_smg_silenced
weapon_smg_silenced_spawn
weapon_sniper_awp
weapon_sniper_awp_spawn
weapon_sniper_military
weapon_sniper_military_spawn
weapon_sniper_scout
weapon_sniper_scout_spawn
weapon_spawn
weapon_spitter_claw
weapon_upgradepack_explosive
weapon_upgradepack_explosive_spawn
weapon_upgradepack_incendiary
weapon_upgradepack_incendiary_spawn
weapon_vomitjar
weapon_vomitjar_spawn
== Alien Swarm ==
asw_alien
asw_alien_goo
asw_alien_jumper
asw_alien_shover
asw_ambient_generic
asw_ammo_autogun
asw_ammo_chainsaw
asw_ammo_drop
asw_ammo_flamer
asw_ammo_mining_laser
asw_ammo_pdw
asw_ammo_pistol
asw_ammo_rifle
asw_ammo_shotgun
asw_ammo_vindicator
asw_aoegrenade_touch_trigger
asw_bait
asw_barrel_explosive
asw_barrel_radioactive
asw_bloodhound
asw_boomer
asw_boomer_blob
asw_bouncing_pellet
asw_broadcast_camera
asw_buffgrenade_projectile
asw_burning
asw_buzzer
asw_campaign_save
asw_client_corpse
asw_colonist
asw_debrief_info
asw_debrief_stats
asw_director_control
asw_door
asw_door_padding
asw_drone
asw_drone_jumper
asw_drone_uber
asw_dummy_vehicle
asw_dynamic_light
asw_egg
asw_emitter
asw_entity_dissolve
asw_env_explosion
asw_env_shake
asw_env_spark
asw_equip_req
asw_extinguisher_projectile
asw_fallen_door_padding
asw_firewall_piece
asw_flamer_projectile
asw_flare_projectile
asw_game_resource
asw_gamerules
asw_grenade_cluster
asw_grenade_freeze
asw_grenade_prifle
asw_grenade_vindicator
asw_grub
asw_grub_advanced
asw_grub_sac
asw_hack_computer
asw_hack_wire_tile
asw_harvester
asw_healgrenade_projectile
asw_health_bar
asw_holdout_mode
asw_holdout_spawner
asw_holo_sentry
asw_holoscan
asw_hurt_nearest_marine
asw_info_heal
asw_info_message
asw_intro_control
asw_jukebox
asw_laser_mine
asw_marine
asw_marine_resource
asw_marines_past_area
asw_marker
asw_mine
asw_missile_round
asw_mission_manager
asw_mission_objective
asw_mortar_round
asw_mortarbug
asw_mortarbug_shell
asw_objective_countdown
asw_objective_destroy_goo
asw_objective_dummy
asw_objective_escape
asw_objective_kill_aliens
asw_objective_kill_eggs
asw_objective_kill_queen
asw_objective_survive
asw_objective_triggered
asw_order_nearby_aliens
asw_parasite
asw_parasite_defanged
asw_pathfinder_npc
asw_physics_prop_statue
asw_pickup_ammo_bag
asw_pickup_ammo_satchel
asw_pickup_autogun
asw_pickup_buff_grenade
asw_pickup_chainsaw
asw_pickup_fire_extinguisher
asw_pickup_flamer
asw_pickup_flares
asw_pickup_flashlight
asw_pickup_grenades
asw_pickup_heal_grenade
asw_pickup_hornet_barrage
asw_pickup_medical_satchel
asw_pickup_medkit
asw_pickup_mines
asw_pickup_mining_laser
asw_pickup_money
asw_pickup_pdw
asw_pickup_pistol
asw_pickup_prifle
asw_pickup_railgun
asw_pickup_rifle
asw_pickup_sentry
asw_pickup_sentry_cannon
asw_pickup_sentry_flamer
asw_pickup_sentry_freeze
asw_pickup_shotgun
asw_pickup_stim
asw_pickup_t75
asw_pickup_tesla_trap
asw_pickup_vindicator
asw_pickup_welder
asw_point_camera
asw_powerup
asw_powerup_chemical_bullets
asw_powerup_electric_bullets
asw_powerup_explosive_bullets
asw_powerup_fire_bullets
asw_powerup_freeze_bullets
asw_powerup_increased_speed
asw_prop_laserable
asw_prop_physics
asw_queen
asw_queen_divers
asw_queen_grabber
asw_queen_retreat_spot
asw_queen_spit
asw_radiation_volume
asw_ranger
asw_remote_turret
asw_rifle_grenade
asw_rocket
asw_rope_anchor
asw_scanner_info
asw_scanner_noise
asw_sentry_base
asw_sentry_top
asw_sentry_top_cannon
asw_sentry_top_flamer
asw_sentry_top_icer
asw_sentry_top_machinegun
asw_shaman
asw_shieldbug
asw_shotgun_pellet
asw_shotgun_pellet_predicted
asw_simple_drone
asw_snow_volume
asw_spawn_group
asw_spawner
asw_stylincam
asw_t75
asw_target_dummy
asw_tech_marine_req
asw_tesla_trap
asw_trigger_fall
asw_vehicle_jeep
asw_voting_missions
asw_vphysics_npc
asw_weapon
asw_weapon_ammo_bag
asw_weapon_ammo_satchel
asw_weapon_autogun
asw_weapon_bait
asw_weapon_blink
asw_weapon_buff_grenade
asw_weapon_chainsaw
asw_weapon_electrified_armor
asw_weapon_fire_extinguisher
asw_weapon_fist
asw_weapon_flamer
asw_weapon_flares
asw_weapon_flashlight
asw_weapon_flechette
asw_weapon_freeze_grenades
asw_weapon_grenade_launcher
asw_weapon_grenades
asw_weapon_heal_grenade
asw_weapon_heal_gun
asw_weapon_hornet_barrage
asw_weapon_jump_jet
asw_weapon_laser_mines
asw_weapon_medical_satchel
asw_weapon_medkit
asw_weapon_mines
asw_weapon_minigun
asw_weapon_mining_laser
asw_weapon_night_vision
asw_weapon_normal_armor
asw_weapon_pdw
asw_weapon_pistol
asw_weapon_prifle
asw_weapon_railgun
asw_weapon_ricochet
asw_weapon_rifle
asw_weapon_sentry
asw_weapon_sentry_cannon
asw_weapon_sentry_flamer
asw_weapon_sentry_freeze
asw_weapon_shotgun
asw_weapon_smart_bomb
asw_weapon_sniper_rifle
asw_weapon_stim
asw_weapon_t75
asw_weapon_tesla_gun
asw_weapon_tesla_trap
asw_weapon_vindicator
asw_weapon_welder
env_global_light
env_slomo
info_marine_hint
info_node_marine_hint
info_tutorial_start
point_event_proxy
trigger_asw_button_area
trigger_asw_chance
trigger_asw_computer_area
trigger_asw_door_area
trigger_asw_jump
trigger_asw_marine_knockback
trigger_asw_marine_position
trigger_asw_random_target
trigger_asw_supplies_chatter
trigger_asw_synup_chatter
trigger_asw_trigger_area
== Portal 2 ==
challenge_mode_end_node
cube_rotationcontroller
ent_hover_turret_tether
env_fizzler_effects
env_player_viewfinder
env_portal_laser
filter_player_held
filter_size
fizzler_multiorigin_sound_player
func_placement_clip
func_portalled
futbol_catcher
hot_potato
hot_potato_catcher
hot_potato_socket
hot_potato_spawner
info_coop_spawn
info_landmark_entry
info_landmark_exit
info_paint_sprayer
info_placement_helper
info_player_ping_detector
info_portal_score
info_target_personality_sphere
item_nugget
linked_portal_door
logic_coop_manager
logic_timescale
npc_hover_turret
npc_personality_core
npc_wheatley_boss
paint_sphere
paint_stream
point_changelevel
point_futbol_shooter
point_laser_target
portal_base2d
portal_mp_stats
portal_procedural_generator
portal_race_checkpoint
portal_stats_controller
portalmp_gamerules
projected_entity_ambient_sound_proxy
projected_tractor_beam_entity
projected_wall_entity
prop_button
prop_exploding_futbol
prop_floor_ball_button
prop_floor_button
prop_floor_cube_button
prop_glass_futbol
prop_glass_futbol_socket
prop_glass_futbol_spawner
prop_indicator_panel
prop_laser_catcher
prop_laser_relay
prop_linked_portal_door
prop_mirror
prop_monster_box
prop_paint_bomb
prop_personality_sphere
prop_physics_paintable
prop_rocket_tripwire
prop_testchamber_door
prop_tic_tac_toe_panel
prop_tractor_beam
prop_under_button
prop_under_floor_button
prop_wall_projector
prop_weighted_cube
trigger_paint_cleanser
trigger_ping_detector
trigger_playerteam
trigger_portal_button
trigger_tractorbeam
vgui_indicator_panel
vgui_level_placard_display
vgui_mp_lobby_display
weapon_promo_antenna_ball
weapon_promo_antenna_egg
weapon_promo_helmet_ball
weapon_promo_helmet_egg
== Counter-Strike: Global Offensive ==
ammo_357sig_np_reserve
ammo_357sig_p250
ammo_357sig_small
ammo_556mm_small
breachcharge_projectile
bumpmine_projectile
cfe_player_decal
chicken
dangerzone_controller
dangerzone_entity
decoy_projectile
drone
dronegun
dz_door
ent_snowball_pile
env_cascade_light
env_gascanister
func_block_dm_spawns
func_no_defuse
func_survival_c4_target
func_tablet_blocker
game_coopmission_manager
game_money
game_round_end
game_survival_logic
global_chatter
grassburn
hostage_carriable_prop
info_armsrace_counterterrorist
info_armsrace_terrorist
info_bomb_target_hint_a
info_bomb_target_hint_b
info_deathmatch_spawn
info_enemy_terrorist_spawn
info_gascanister_launchpoint
info_hostage_rescue_zone_hint
info_hostage_spawn
info_map_region
info_paradrop_denial
info_player_ping
item_cash
item_coop_coin
item_cutters
item_dogtags
item_heavyassaultsuit
mapvetopick_controller
npc_heardanger
paradrop_chopper
planted_c4_survival
planted_c4_training
point_dz_dronegun
point_dz_itemspawn
point_dz_itemspawn_group
point_dz_parachute
point_dz_weaponspawn
point_dz_weaponspawn_group
point_give_ammo
point_hiding_spot
prop_ammo_box_generic
prop_counter
prop_dynamic_glow
prop_exploding_barrel
prop_loot_crate
prop_mapplaced_long_use_entity
prop_metal_crate
prop_money_crate
prop_paradrop_crate
prop_weapon_refill_heavyarmor
prop_weapon_upgrade_armor
prop_weapon_upgrade_armor_helmet
prop_weapon_upgrade_chute
prop_weapon_upgrade_contractkill
prop_weapon_upgrade_exojump
prop_weapon_upgrade_helmet
prop_weapon_upgrade_tablet_droneintel
prop_weapon_upgrade_tablet_highres
prop_weapon_upgrade_tablet_zoneintel
radar_jammer
snowball_projectile
survival_spawn_chopper
tagrenade_projectile
trigger_bomb_reset
trigger_safemoneygather
trigger_softbarrier
trigger_soundoperator
trigger_survival_playarea
vgui_world_text_panel
weapon_bizon
weapon_breachcharge
weapon_bumpmine
weapon_decoy
weapon_fists
weapon_galilar
weapon_healthshot
weapon_hkp2000
weapon_incgrenade
weapon_knifegg
weapon_mag7
weapon_mp7
weapon_mp9
weapon_negev
weapon_nova
weapon_p250
weapon_sawedoff
weapon_scar17
weapon_scar20
weapon_sg556
weapon_shield
weapon_snowball
weapon_ssg08
weapon_tablet
weapon_tagrenade
weapon_taser
weapon_tec9
weapon_zone_repulsor
weaponworldmodel
== See Also ==
* dump_entity_sizes
* List of All Entities in Valve Source Games