This is a good base for a puzzle game, I like that!
Simple, short and efficient, and I liked the little suprise at the end allowing to see the test chamber where all features were tested;
For bugs, well I got soft-locked twice. I deserved it the first one because I returned without the orb which I didn't found but couldn't return to the dungeon because I've managed to steal the torch of the tutorial I wasn't supposed to carry with me! (take that master for telling me I should not take it with me :P) but for the second time, I've just been too slow to cross the trap door... and it re-opened itself before I could cross it... So without the iron key respawning I was unable to go further!
But at my third attempt, no soft-lock this time, I've completed the game and enjoyed it!
Good job!