Nice game. I really like switching eras between levels, and it’s great that we get different weapons and abilities on different levels.
Enemies don’t differ that much from each other, and the boss on the first and third level feels pretty much the same mechanically. The boss on the second level, though, is great.
There were two gameplay things I didn’t like. First, enemy bodyblocking, when a few enemies surround you from different sides, there’s basically no way to escape. I’d probably remove player blocking by them entirely.
Second, when boss #2 pushes you while you’re against a wall, it feels like you lose control, as if the push vector keeps pulling you while the wall blocks movement (that’s how I’d diagnose it). That didn’t feel good either.
I saw some people complaining in the comments about the screen shake on the first level, but I actually liked it.
Overall, a solid game.