Great job for managing to do all the assets within the jam period!
The black hole using objects to recharge is an interesting design. It would be great if there were more objects. I tried and it was a nice surprise that the round hovering enemies can also be transformed into energy. But the turrets did not seem to be transformable which would have been nice.
It can be rather punishing that enemies can see (and shoot?) through walls. If I designed the game I would rather be on the lenient side and make the game easier on the player. To avoid rage quitting.
Good luck!