I ended up submitting my game yesterday as I started late, I only spent around 8 hours on it, but it works well with only a few bugs. In the year 3030, you are the last line of defence between Earth and some cardboard boxes. Defeat the swarm of 99 cardboard boxes to save Earth. Fail and Earth will be destroyed.

Play it here http://www.ludumdare.com/compo/minild-42/?action=preview&uid=13768