Neat little game. I like how you used a dual meaning of the theme. The box placing idea is interesting, but probably needs some limits to make it require more thought. I started off by carefully crafting box stacks to reach each next platform, but eventually realised you can easily ascend by just jumping and placing boxes beneath you. Perhaps there could be a limited number of boxes on screen, or maybe you could only be allowed to place boxes while on solid ground. Still, not bad for your first jam game!