Great entry! I didn't like the sliding and loved that I could upgrade that. I think the game was a bit too long, I made it to 15 or 16 (also, I had to stare for a while to read "terminated"), the first 7 levels were fun but levels become so long. The only real threat was the warping ghosts, nearly 100% of my damage was one warping into me which felt kinda lame. I'm real torn on how the castle changes, on one had I liked that I got into the rhythm of "there's probably a fast ghost that'll charge in" but it did feel repetitive, especially 10+.
I'm also unconvinced the damage upgrade did anything, maybe it helped but was so outpaced by the shielded ghosts and then warping shielded ghosts, I would have dumped it all into reload speed instead.
Scanning the other comments, I also didn't like the ghosts piled up behind the locks. An easy fix could have been making the lock larger (or two) so there was a little breathing room.
This is jam and I'm no stranger to overscoping so these are just ideas, again, great job!