I just downloaded and played your program. You did a pretty good job overall. This is a very good piece of work. It was fun to play for me (23 years old. ) Exspecially the lava world is hell of atmospheric.

Never the less i found a two things to fix:

At a moment in the program i was asked to solve the following exercise:

3
*
---
?

Leaving the field blank turned out in being correct. Entering 0 is the same. So I guess there is meant 3 * 0? But this exercise was not given before. The one before was 1 * 3. So i was a little irritated.

Second the PC got sometimes stuck in the turning platforms in the Techlevel. Loading the last checkpoint solved the problem.