Okay it took me a moment to figure out that I was placing blocks of code and that where I was placing them mattered. If the top part of the screen looked more like a bunch of empty slots waiting to be filled by the commands, I think people would get it much quicker.
Once I did understand the game, I was disappointed by how quickly it was over, because the idea is brilliant!
My first programming experience was with a game called Lightbot, which worked similarly with you "programming" your bot and then executing the program to complete the level. But this game takes it a step further with the up and down arrows, bringing your line of code into the second dimension!
There is SO much potential with this idea, I hope you develop it further! There's a lot to hope for in terms of game feel, but the core idea behind it could really turn into something amazing.