very cool idea, the only real issues i had were on level 5, its a bit tricky to know which cubes are gonna clog the hole first, i had to do a few tries cause i kept having the roundish one clip into one of the cube ones… also, its not immediately obvious which direction pressing “down” will go on the isometric angled view, though thats not a big problem and at worst makes you burn a turn or two.
overall i really like the idea, levels 6 and 7 reminded me a lot of that old flash game bloxorz. nice job!