Thanks for playing the game, yeah I really liked the concept too, it was a lot of fun to make. I think the main thing that I don't explicitly say in game which is most likely where the confusion comes from is how to tell the difference between ice and floor if its in a corner or next to a wall. Basically if you slide onto a tile and then without touching anything bonk the wall that means the tile is ice whereas if you slide onto a tile and stop immediately without bonking into anything that means that the tile is normal floor and not ice.
But also yeah I level select mechanic would be nice to add just in case you want a refresher or skip over it too quickly I agree