itch.io

I think the reason they felt unresponsive to me is because of the inconsistency of the acceleration and deceleration of the player. Which gives the player an unreliable feeling of weight.
Changing direction while walking is slower than changing direction while sprinting. You reach your max speed much sooner when you sprint than when you walk.
When you stop moving while sprinting, you slide across the ground. Which can make it feel unresponsive. On the opposite side, when you stop moving while in the air, you stop almost instantly. This makes for clunky feeling in-air movement imo. I find it feels better to keep some of your momentum when you release the movement keys while in the air.
Another thing I noticed was that the player seems to go up faster than they do going down when jumping. This can also give a very clunky feeling.
I personally would make sprinting the default when moving and have walking be a key press. Because to me, walking felt very slow and encumbered.
And lastly, I would recommend adding coyote time to your jump. It makes for a lot nicer feeling platformer.