It's actually really fun, I like the progression, feels good when the character is getting faster and stronger almost every stage. The graphics are basic, but totally fine for a jam game.
The auto aiming was a great idea, I also faced the problem of only 4 directions with my game ideas, I wish I had though of that!
In the end I had a bug where my character wouldn't die even well below 0 HP. I have to admit, I played on until my char was pretty much flash with a gatling gun. haha
Anyways my score before I dropped below 0 HP was 7950.
The only complain I would have is that you often spawn into enemies, that's pretty annoying.
Nice game, very fun, well done!