I see I see, I'm not too keen on platformeres but I had learn a lot throught the years. if it's okay with you I'll tell you some of it.
- jump frames, if you're still holding on the jump button it will still jump until the max jump length capacity.
- cayote time, there will be a small time frame that the player can still jump after leaving the ground.
- jump queue, the player can press jump even before touching the ground. it makes the morer feel responsive.
- stop acceleration, it gives a little bit of time to fully stop the character, this prevents the character looking robotic
- squash and stretch, when jumping and landing making it looks like polish and alive.
there's probably more but this only I can say in top of my head.