Great job submitting a game! I like your minimal visual style and sound design. It seems like the bugs you mention as fixed still exist. The first boss started invisible and my one bomb didn't carry over to level 2. I actually thought the invisibility was a cool little boss gimmick, firing at empty space and then hitting him made him appear which was a neat surprise.
I would prefer a little more precision in the movement. There was a floaty-ness/delay which made me take a few hits. I really liked all the tank sprites and the upgrade progression. The different attack styles of enemies was a neat touch which introduced some diversity to the gameplay. Thanks for participating!