Is there a way to change the jump height of my player without changing his speed? My player jumps very high and I want to lower it. I tried lowering the speed but that didn't do anything. I like its speed as is though. Also, I used a different sprite for my player and my sprite is smaller than the one used in the videos, I don't know if that affects anything.
You can change only the Y component of the speed variable. If you mean you like the speed at which the player leaves the ground at, then you can change the amount of gravity that affects the player - it will slow the player down faster and thus create a shorter jump.