A few issues (in lieu of posting each separately)

[ron-wolf]

• Animation: Mario’s walking animation stutters when turning around.
  • It seems like the first part of the walking sprite isn’t displayed for long enough, or possibly Mario goes into the standing animation before continuing to walk in the opposite direction.
• Controls: Holding down “jump” results in repeated jumps rather than just one.
• Physics: Alternating between ← and → (or A and D) results in continuous acceleration rather than temporary deceleration.
  • This seems to be an issue only when the keypresses are in quick succession, i.e., while Mario hasn’t yet reached full speed over the course of a single keypress.
• Physics: Holding down a direction and pressing ↓ / S repeatedly results in alternate acceleration and deceleration, rather than just deceleration followed by repeated crouching.

I presume this isn’t a serious project though, so you can close this issue if you want. I’m not really posting it with the expectation that you’ll fix them, just as a challenge if you ever feel like returning to this—or to anyone else who wants to work on it. It’s a really neat project!