You dont have to add check points everywhere. Add them every floor and I am pretty sure you can still keep the game's difficulty by choosing to place the player somewhere a little far but not too far from where he died. Also, as for my game, I believe it only gets difficult as you reach level 3 and dead difficult once you move to level 5. And yes I should make it somewhat more easier but I don't die as soon as I touch objects like in this one.
Also, I know the reason why you chose pixel art font for homescreen but the problem is that I couldn't understand what the instructions are saying to press for jump. 🙂