This is poorly optimized for web but it runs and is beatable.

It was keyboard and controller support. Move with WASD/LeftStick, aim with Mouse/RightStick. Shoot with Mouse1/RightTrigger, jump with Space/BottomFaceButton

As you explore the turtle's organs enemies will spawn. When you have cleared all the enemies from an organ you will get a message saying the organ is cleared. Clear all organs to win and return to main menu.

There is a bug where alt tabbing or other things can cause the mouse capture to break, if this happens, sorry. Controller still works tho!

Oh also you can't die. you have a health bar but nothing happens if it reaches zero, so the fact that health pickups never got implemented is not as big a deal :P