Very fun, challenging and unique
I love logic games and this one was definitely tough. If you built on it it would easily become a classic. I had most trouble on the 2nd to last level (10 i believe), but the next two seemed increasingly easy.
Still needs more though, such as a second series of levels with a third, forth... function unlocked or different obstacles (switched doors, gaps)/additional commands (push, pull, climb, reverse function - to perform a function in its opposite order)/ additional objectives such as activating lights in a certain order or pushing/pulling blocks to make paths, fill gaps or to activate switches.
Although the best part of this game seemed to be its simplicity, I couldn't stop playing it until I finished it - so with some additional even more challenging levels I'm sure I would have been up all night trying to beat it.
As for what you did have, here's what I think you could improve: 1) I'm sure someones already mentioned a level editor. 2) It'd be even harder if you made it so each level had a set number of commands for that level, ie level one would only have 2 or whatever spaces for commands (whatever the maximum needed for the level) / the first few levels wouldn't have the function ability until you get to level where you need it. 3) Add a hint or solve option. 4) let the difficulty build up more gradually and continue to build up (like I said before i had more trouble with the 2nd to last level than the last two).
That's all I can think of right now. It kept me entertained for few good hours so I figured writing more than "the game =ed fun" would be the least I could do. Keep up the good work I'll have to try your other games. 10/10 5/5 fav.