The game has a nice cohesive feel.
As an asset pack addict, its super impressive that you made all the assets yourself.
The biggest issue is that it feels padded out. Given the limited amount of unique content, which is 100% understandable in a game jam, the levels overstay their welcome, lasting too long and becoming boring. I think it would be better served by simply reducing the repetition in each level so they are shorter.
The second main issue is that shields seem too generous. I can AFK in certain parts of the screen and my shield will just block all damage. The regen rate should probably be slower.
But overall, it's a well-done game and captures that arcade feeling.
Good work.