Decided to play through the whole game again to reassess it because I think my first time through was marred a bit by misplaced expectations. I do think the game is better than I originally thought, but a lot of my complaints are still valid.
Pizza Tower is a very good game, but I believe the level design being so focused on P ranks ends up hurting it. Instead of being the Wario Land inspired game it advertises itself as, it almost feels more like a less punishing Super Meat Boy or a very linear 2D Sonic game. It's less about going with the flow of the level and freely doing what you want and more about memorizing which pixel to press the jump button at the right time. Very much a game designed with a speedrunner's mentality. I definitely much prefer exploration-based platformers like Yoshi's Island, Mario World, Wario Land 4, etc. than this type of thing.
I also still think the bosses are oddly out of place too. You literally cannot die in levels, so having bosses be this much of a difficulty spike is jarring. Plus I generally tend to dislike this style of 2D platformer boss fight where you're just dodging attacks until an opening appears. It feels lazy at this point. Granted, this game does it better than most, and the final boss is genuinely fantastic.
With that being said, Pizza Tower is still really fun. You can play it more slow paced even though it's very clear you're not supposed to. There's a lot to appreciate here, like its music and it's animation. It's not the masterpiece terminally online zoomers claim it is, but it is definitely good and worth playing.