I just updated this thanks to people in sunbla's chat being sure I knew most of what went wrong technically.
Update fixed the tileset, backgrounds, the sounds and music, as well as moved a single mini-spike 6 pixels up as per PlasmaNapkin's suggestion. There's also now a spike on the second screen placed that I had forgotten to place in the first version. Thanks for playing.(this game sucks imo.)
I won't be updating this further unless someone finds something gamebreaking like sound not working again.