I hope this helps! Read the Notes and Credits for what I changed. The player now no longer changes costumes while in midair. Still needs many things. Plenty of glitches remain: -When standing, the level jitters up and down. A side effect of the jumping mechanism. -When walking, in the middle of the step the level stops registering contact with the feet, causing it to drop in the middle of the step. This could be explained as a walking motion. I corrected this by making it change y by one when touching the ground. This caused the next issue: -When pressed up against the wall on the bottom level, it registers connecting the leg, making the player gradually move upwards. This could become a ladder-climbing mechanism.
I changed the gravity system, and reprogrammed everything. The program now uses only one variable. I also changed the graphics so it is neater. I increased the sideways movement speed and changed the jump. I changed the character to @cheezepuff's Ronan. This was to cope with a glitch were the legs would lag behind. I changed the color of the platforms from black to grey at the suggestion of @Mida06.