Great game!
I love all the artwork and animations for the player/enemies. The effects for damage, turret laser, explosions, portal, and the boss movement is really good! The game really has potential if you decide to keep working on it.
I would be nice to have a way to recover energy other than killing enemies. Like during the boss fight, there was no way to get more. Maybe natural regen or when damaging the boss?
The sound effects were also good, but a little loud by default. Though no problem for a short game jam. Great work!