Also, there is a glitch wherein certain players become invincible but are also unable to deal damage. May be a brick somewhere.
This is caused by bad eventing and not enough safety checks to make sure the datablock gets changed. When you spawn, you are probably the
Non-Combatant Player (a modified version to remove jet). When you leave the spawnroom, you are
supposed to become the No-Jet Player, but you don't. It probably happens if you knock down a wall instead of going through the teleporter to get out.