Great feedback, thank you soo much!! As the level/game designer (mos), I'm really glad you liked the mechanics and the difficulty! It's nice that flinging the character was something you thought was useful, with the second level's design we tried to teach this and I'm really happy you understood that you could give Juan momentum with the board :D
About Juan being slippery on the board, yeah, it felt off to us too... We tried to fix it making their physical material's friction very high, but while it kinda made Juan stick to the board if you moved it slowly, it made fitting through tight gaps with the board very frustrating because it would get stuck... We would have liked to come up with a good solution for the problem but we didn't have enough time, so if we keep working on the game and release an enhanced version, this will be one of the things we'll try to fix.
I'm relieved that you didn't find it difficult by the way... At first we were going to give just 3 seconds of jetpack to the player and you could juuust beat the levels, but many of the people who tested the game said it was a bit unfair, so we changed it to 4-5 seconds. And even with that change a lot of players found the game difficult! Not everybody has the same skill of course, but I'm happy that somebody found the difficulty was fair ;)