Schizoid

In _Schizoid_ , which calls itself “the most co-op game ever”, a red ship and
a blue ship battle red and blue neon glowing enemies. The red ship will
destroy any red enemy it touches, but will be destroyed by any blue enemy; and
vice versa for the blue ship. The result is that the red and blue ships must
work together closely to alternately guard each other and smash enemies. Lives
are shared, making this a pure co-op experience for 2 players – or 1 player
can play with a computer AI, or control both the red and blue ships
simultaneously with the two thumbsticks in the hardcore “Uberschizoid” mode.

_Schizoid_ has 119 levels, divided into 7-level “chambers” with a save
checkpoint at the end of each chamber. If you beat a level without any life
losses, you get a gold star on that level; whenever you lose all your lives
and go back to the last save checkpoint, you will skip past any level you’ve
“golded”, providing a big incentive for completing a level perfectly.