This game was fantastic! Very unique take on the theme and limitation. I loved the Luftrausers-style gameplay and the fact that there was a solid variety of ships and upgrades for a 72 hour jam was impressive.
The graphics are a little rough around the edges - the in-game timer and score is in what feels like a default font - but the rest of the game is so polished I have to let it slide.
If any game in this jam were to be developed into a full game, I'd really hope it was this one!