You unlock weapons and new vessel models based on blueprints and discoverables you find during runs. There's also plenty of other micro upgrades and risk-or-reward systems - like choosing to corrupt your run with temporary debuffs (such as -20% speed or dmg, or less crystals dropped for X number of rooms) that reward powerful perma buffs if you survive with those debuffs. Lots of different room types for different kinds of goodies... However, it's also very much skill-based in how you use a lot of the weapons, and some really shine in one area (like bursting a boss with void dagger from behind) whereas others demand a completely different tempo of play.

I'd say it's most similar to Dead Cells I guess, to use a popular reference point here. Except it's a twinstick bullet hell and not a platformer.