The goal is rather unclear. On my first go, I tried to utilise the free space as much as possible, but the boxes come in so fast that planning for the long run becomes close to impossible. Getting the three "purple particle systems" extinguished -- i.e. losing -- can happen in about a second.

Since there doesn't appear to be a score penalty for replacing a placed box, the best strategy I found is to simply spam right-clicks in the middle of the area, and place any extra boxes carefully if the time/input volume allows it. The score keeps ticking up, and we are absolutely immortal.

All in all, I'd say this has potential, but I can't say much more than that. I like the particle systems when boxes are destroyed though, and the placement feels nice and "solid". Tiny details like these are very nice to see.