Servers

When entering Gethsemane, players are allowed to choose from a variety of server types. 
Vanilla - is a pretty typical VRMMO, aside from the significant boost in sensory immersion. Fixed NPC's, a theme-park quest system that provides the same experience for every player, fields of enemies that sit there and wait for you to arrive sometimes performing very simple routines, and a combat system with mentally selectable buttons that pull the player through the motions of an attack. Nothing particularly inspired. 
Sandbox - abandons the idea of the Theme Park, and replaces it with behaviors. Rather than a field of mobs, there's an ecosystem; plants grow and spread seeds, weather patterns affect plant growth, herbivores eat the plants, predators hunt the herbivores and both spawn based on the ability to sustain a food supply. Rather than NPC's who stand around and endlessly perform the same tasks, the NPC's have lives, habits, participate in a active economy, seek out resources and re/build/abandon towns as war, the economy and their personalities dictate. Politics happen in real time, with trade deals, grudges, wars led from the front, intrigue, espionage and diplomacy. And in the background, the plot happens, not as a series of static events, but played in real time by actors. 
Simply... the world lives, and every player action matters.
Hardcore - takes off the training wheels. It isn't an advanced setting of sandbox, with a normal hardcore server all the classic elements of a Themepark MMO remain, but rather than the system guiding the players movements when triggering an ability, the player has to perform the ability themselves. Training isn't a conversation a short quest and a click of an icon; it's advanced training. The blade must be swung, the spell drawn out and chanted, the crafted item carved and hammered into shape, so on and so forth. 
Many ask why a person would go through this when a game is meant as an escape, but there's a pretty dedicated audience to whom that IS entertainment, and there are two bonuses that most consider sufficient reward for this extra effort. The skills earned on a hardcore server can be used IRL, and Hardcore adds sensory input for touch, smell, taste, sex, and several levels of proprioception that keeps most games from really being accepted as immersive; where classic and sandbox only have sight and sound. 
Lewd - In other servers sex is a thing that can happen. the specifics are different for each server, but its there and it's accessible. In a Lewd server, situations fold themselves in half more than porn in order to shoehorn sex into a situation. Plants develop tentacles, animals will rape rather than maul you, bandits will sell you to a brothel, cultists will toss you in a pit with a tentacle monster rather than cutting your throat or pulling out your heart while you're waiting in the respawn room; ect, ect, ect... That being said, a standard lewd server is only slightly more titillating than any other VR Porn. 
Hardcore Sandbox - is the endgame for fans of Gethsemane. It's as close to reality as you can get while still being surrounded by fantasy and syfy elements. All User Interface measures built up over 50 years of gaming have been converted into trained abilities and physical items; NPC's are indistinguishable from other players except perhaps because they don't recognize pop-culture; and dying no longer comes with free respawns. A healer, special item or contract with a hero-altar can resurrect your character; but forget this, and you have to start over from 1. Well, not quite, YOU the player, still remember your skills, and can use them on your next run; but relationships, gear and position are all gone with your corpse. Not that this is always a bad thing; players with a habit of gathering enemies or traumas see this a means of getting a fresh start, going so far as to create supply cashes in preparation for their going out rampage. 
Lewd sandbox - takes the facets of lewd and sandbox to their logical conclusions, whereby relationships are the focus of both the living world and the shoehorned fanservice. Expect harems, stalkers, family dynamics, romcoms and other porn with plot. Rather than just porn. 
Hardcore Lewd - In Lewd and Lewd Sandbox, it's a porn game; in hardcore lewd, the sex is indistinguishable from life. Or it would be, save for the content. 
Hardcore Lewd Sandbox - Much like hardcore-sandbox, but the world is much darker. Sex is around every corner and a pillar by which the NPC's, mobs and society functions. While there is a dedicated fanbase for this server... it's small. Even by comparison to the other servers limited populations. Brothels are everywhere, slave markets exist and mostly cater to fetishes, as do monster pens; and nonconsensual rape is an issue as cultists and warlocks lose control of their pets and start demon wave events.