Very strong core gameplay, with a simple and easy to understand core interaction but a lot of depth that stems from it. It would be cool if abilities interacted more, for example, if the max shield upgrade increased your max health when you had the perk that turns shield pickups into health. Still, the abilities themselves are all fun to use, plus it's really satisfying to go from having to save every hp, shield, and coin you can early on to being able to play more aggressively with some health regen perks!