Its true, I didn't have a lot of time to balance. A lot of the levels have a strategy to them (oftentimes that strategy is "get to a safe corner as quickly as possible, and don't miss your shots"). If I lock in and really focus on the swapping mechanic, I can consistently get to level 7. There's no end to the game it just randomly picks levels forever, more of a high score/arcade type of game.
Thank you for the feedback :)