Not 100% sure how to properly play this game tbh, it could use a tutorial video and a better explination really. I did like the idea you were going for and the simple art style works well. As for your saving and loading, that isn't that hard in game maker from what I recall. I made a game back in 2014/15 (GM 1.4) that used .ini files for level status saving. it was just a matter of opening, writing and saving the file. Not sure if GM 2 changed how that works though. I'd recommend looking into it as its a good feature for any game really.
Still a good effort, well done!