I've uploaded a small update for the preview build. Here are the changes:

• You can now use Y/Z to jump (in addition to C/Space)
• I've reworked stage 2-2 to better teach a mechanic needed later
• I've made a small change to 2-9 to make the intended path clearer

If you're using the itch.io app the game should update automatically, if you're not I'd recommend downloading the game again.

Also, if you're interested, I've written a detailed blog post on why I felt it was necessary to rework stage 2-2. I think it's a classic example of teaching via level design gone wrong.

Finally, this is what 2-2 looks like now: