Initialy, I had an acceleration code, but because of the super low resolution of the game, it made the character and the camera really shaky and it felt bad. I also simply tried switching the game to 30fps and it solved that problem but I didn't have enough time left to adapt the whole game to 30fps.
Instead, I made the pits no longer taking away some of your life, going back to the begening was enough punishment.
But personally I do like the silky smooth touch 60fps brings.