While I enjoyed the game overall, there were some dumb decisions in the game. I honestly am fine with the linearity of the game, however not being able to backtrack at the very end of the game and being locked out of certain rooms is just dumb and makes the end feel kinda lame. I like being able to try and get stuff, and unknowingly locking myself out of that is kinda unfair, especially on an initial playthrough. Also, I hate the dumb X parasite mechanic where you fight another enemy after killing a boss. Most of the time it was fine, but I have died multiple times after beating a boss just because I have like no health, and then I have to redo the entire fight, which feels awful. Might be the worst one I've played for those two reasons alone, which is sad because otherwise I enjoyed a lot. Bosses felt a bit harder than 1 and 3, which was nice. It was cool getting a few new upgrades, and I liked that some came from beating bosses.