Complex sentence: Once the player is confident in their skills, they can enter the Budokan where the player faces consecutive opponents equipped with various weapons (including, but not limited to, those available to the player).
Split into simpler sentences: Once the player is confident in his or her skills, the player can enter the Budokan. In the Budokan, the player faces consecutive opponents equipped with various weapons (including, but not limited to, those available to the player).