> The run speed is way too fast and the animation that goes with it is rather jilted.
By the way, I forgot to mention this anywhere, but you can move slower by holding Shift. I guess perhaps switching that around and making walking the default might fit the tone better in this case? (Or are you referring to the weird glitch that causes you to move fast (among other things) if you press up or down in certain places? That's related to the glitchy unfinished climbing feature where the character will try to "climb" bumpy/hilly surfaces as if they were walls. That might also be why you walked in air.)
> Also the jump is quite high.
You mean a bit too high or were you expecting a more realistic less-than-your-body-height jump? If the latter, then it may just be a difference of what we're used to. (Oddly enough, I just tested the jump height in a few different platform games I had and it was much more consistent relative to character height than I was expecting.)
> when I was at the tree with the tire swing I pressed down and slowly went into the ground.
Known bug, didn't catch it in time to fix it. (The character doesn't actually move down when that happens, only the graphic does; making the character and graphic positions separate was probably not the best idea I had...)