Misalignements on:
just basically every freaking room with conveyors, spikes or dissapearing platforms on the edges of the screen
some enemies pass right through the checkpoints, causing massive deaths if you respawn when they are around. remove the enemies that do this, or better yet, remove the checkpoints that are on the path, there are too many on the rooms where this happens.
once you get to space, you cannot progress, the warp gate does not get away even after you get all the trinkets near the entrance