Pretty surprising choice to use Godot for this, it's pretty cool so far!
The movement feels too fast though and doesn't have that ease as you slow down, just tighten up the physics and it'll be great!
How would you like the physics to be modified? if you'd like, you can modify tux's physics and make a pull request on github :D
I have added an "Auto Run" toggle. If you turn this off, Tux handles more slowly by default and has more ease when slowing down.