Amazing game, really well done!
The short introductions for each invader really help you get the hang of it, and the graphics are clear and concise. Seeing those little guys march to the beat made me happy. And the fact that you managed to include custom levels is impressive!
One thing i noticed is that if you make a mistake (crash, friendly fire, etc.) the level resets instantly, and you don't have the time to see where you went wrong, which is a bit frustrating (i ended up replaying broken formations a lot to try and figure out where the problem was).
Also, it would be cool to have an indication of the columns, so you don't have to guess how many steps away an enemy is.
Really cool game, one of my favorites from this jam!