There is literally nothing fun about:
a. A blind drop into spikes
b. A blind drop into an enemy that may or may not be underneath you
c. A blind drop into a room full of enemies
d. The first boss (who I ended up jumping over)
e. Spikes you can walk into the side of
In hard games that feature these sorts of things, there's often something else going on that is balancing out the risk/reward factor and there's often a layer of progress on top of whether you reached the checkpoint or not.
There's a lot here that's really promising, but some of the level design choices contribute to a building sense of bad faith that eventually just makes you give up when the game finds a new way to screw you over.