I got to 252m and then my screen wouldn't let me scroll any more. This was fun, though I actually felt like things were almost too stable. I basically made a single tower of boxes and couches and put everything else off to the side and that worked really well; I feel like making things a touch more wobbly (if you have the ability to control that) would make things a little more chaotic. I agree with the comment below that I would have also liked more ways for things to catastrophically fail (more things like the battery to set off the explosives. I also felt like some music and sound would really add to the experience, but it's tough to do so much on such a short timeframe.
I enjoyed my time with this one. Good work!