EDIT : FIXED I want to speedrun that game but I have an annoying bug. I am unable to beat the last boss because he is so quick that i cannot reach the end of the level before him. (even with v-sync enabled) I have find the origin of this‚ it is because my laptop has a 120Hz monitor. The only way to solve the problem is to limit the game framerate to 60fps but the game become extremely slow.

Here is exactly how my problem lools like :

Does anyone has another solution to my problem?