So I played a bit more, and my reaction has become more subdued. The biggest problem so far is that the game is far too easy (there's a higher difficulty you can unlock once you've completed the game, but I would have preferred to play on that difficulty from the start). Controls are fine and every new area has novel creatures with different and unique attack patterns, but once you've seen them it's easy to avoid their attacks. Even most bosses I've killed on the first try.
The more you play the more you can also see how the randomizer for the levels works. Mostly long horizontal and a few connecting vertical corridors that make for a sprawling level structure, where its easy to plug in the various hand-crafted elements. But the maps look kinda samey and feel less appealing than the hand-crafted areas in say Hollow Knight, where you had areas with a dense, complex, intricate structure as well as sprawling levels and everything in between.
The problem is, unlike say Rogue Legacy or Dead Cells, the randomized nature of the world doesn't add much to the gameplay and isn't really integrated into the core gameplay loop, it's just there as another feature. In theory you could, once you finish the game, play again and see some variations, but so far it looks like most of the major elements (the town people you can save, the fetch quests, items, skills, even the one puzzle in the catacombs) are basically the same in every run, which makes replaying it afterwards more a chore.
It just feels that despite how well it controls and how nice the pixel graphics looks, there's not too much memorable substance below the surface. It's fun to play and shows a high level of polish, but at the same time it also feels somewhat empty and small. I've killed King Trell and are at roughly 80% after around 7 hours, so probably 8 to 9 for the whole game if I'm lucky and I don't see myself getting back to it for more. At 20$, I would say you have better choices.
Also, just for deama, the upgrades are pretty conventional (wall jump, diving, a lamp, claws to hang from ledges, etc.).