Tarbaby Quake allows you to play through Quake as the Tarbaby, Spawn, Bouncy Blue Blob or whatever you want to call them. Your mission is take over Shub-Niggurath's empire.
The Tarbaby player has some more abilities than the other Tarbabies. Player can jump from any surface (and climb up walls), fire rockets, proximity mines and do a heal/bomb/teleport combo. Player also gets more health when bouncing into enemies (zombies are a pretty good health source). Most items in the levels can't be picked up, but all the important ones can be, like keys, powerups and runes.
Player can also develop the character by gaining Character Points from doing damage to the enemies. These can improve damage, jump speed, health and energy for the rockets/mines/healing.
The other Tarbabies are friendly and try to attack your enemies. They may still try to bounce at you if they don't immediately find anyone else to bounce at. It won't hurt.
Most of the new actions can be changed from the customize controls menu.
Fire Rockets = Next/Change Weapon.
Fire Proximity Mines = Previous Weapon.
Jump Move = Jump.
Heal/bomb/teleport combo = Attack/Fire.
Character development done with numbers from 1 to 5 (can't be changed from the menu). 5 activates the "Character development menu".
Forward/Back/Strafe/Run keys don't do much, but can be used to stop movement a little and some other fine control (note: FTE allows regular movement for player with these keys.. that is not how it should be).