Vampire Survivors is a great little Robotron/Crimsonland-esque game in EA. Much more content planned than implemented, but it’s only 3 bucks and could certainly occupy a few hours.
You don’t shoot. You move and everything else happens on its own, but there’s a real rhythm to it that is surprising, because some attacks might shoot the direction you are facing or a particular direction. So, you might be moving away, but want to switch directions when you know a certain attack is about to happen. You aren’t making music here, but it kind of feels like one of those games where you do.
There are character unlocks, item unlocks through accomplishing certain things, and meta-progression. Not a looker, but way more fun that you might think, just looking at it.
One other thing I really like about this is that it’s tense, but not terribly frantic, especially early. I wouldn’t describe it as twitchy.