Well, this is an interesting game! I love the mechanics of moving only at the line with the same color. Even with simple graphics, you've managed to pull off something with good gameplay :)
I do have to admit that I had a hard time figuring out the controls at the first try, though. I kept clicking all the keys in the keyboard and clicking randomly with my mouse, until clicking the box did something. After that, I was thoroughly enjoying the gamplay. I think there was one level though where some red enemies moved when the box is placed at the blue plate? I think the enemies weren't colored correctly in that area.
Can't wait to see you expand on this!