Juho, this game is way too hard. at least for me, skill issue but I hope you don't mind adding a save system when you have enough free time. If the no save system is just a "feature" of the game then don't add it I guess, it's more faithful to the animation and the original Super Mario Brothers without one.
Viewing post in Little Runmo - The Game comments
if u wanna still be able to play through the different levels check out this mod that lets u teleport to every level https://rokle.itch.io/little-runmo-spqol-mod