Downloaded earlier today to see what it was like for a wee bit. Gotta say lad, the presentation and ui you have here is absolutely stellar!
Even though it may be more preferable to have a sort of tutorial mode within the engine itself for easy access of sorts (I remember seeing something along those lines from a Twitter post someone made as a possible addition at one point), this will still be loads of help for new folks starting out. 😃
My only critiques (They're honestly nit-picky, but I thought I'd mention them real quick in case they helped):
When I did the practice level to turn the robot 0.5 radians. For fun, I tried rotate((PI * 2) + 0.5) to see if it'd still qualify as a completion, since it's basically the same as before but only slightly more complicated. It didn't qualify because it's still technically more than 0.5 lol. Just wanted to throw this out there since I felt it could've rewarded for some clever/creative/or even other strange ways to still complete a goal.
No sound effects or music. Not a big deal really, especially for a learning app. But still would've been a nice touch personally. As well as an optional setting to enable/disable them.
But aye, this will be very useful to refresh myself or others on stuff outside of using docs too if need be. Great job friend! :3