This is Sanguine, a procedurally generated bullet-hell rogue-like. It has multiple stages, random levels, upgrade pickups and a final boss.
I made this for the Mini Jam 118: Vampires jam on itch.io over 3 days, mostly by myself, except for the regular enemies that were made by my friend.

You can play it here: https://bunpirate.itch.io/sanguine