Congrats on making a complete game with a lot of charm! This was a memorable entry.
I also thought the movement was a little slippery, but it wasn't game-breaking.
I got stuck for a little bit because I didn't realize I needed to pick up an item in the save room. Eventually I figured it out and beat the game.
I tried putting in the code at the start but I couldn't get it to work.
FYI: Loading a save in the browser version loads you to your last position, but without any upgrades.