I think that there's a lot of good changes in this version!
Something to think about is the health scaling.
When you get to the point that the enemies have 3 health, you essentially have to hit multiple enemies with each bullet in order to break even with the cost you are spending to continue playing.
If you were to iterate further I'd consider some enemies that come from the sides or the bottom, maybe a way to make the bullets shotgun spread.
I think you've got the bones of a really neat 2d 'arena' shooter here!