Sand Box for NewBies - Add Destructable respowning Boxes(targets)

Simply Adding some say.. boxes classified as an enemy unit in Sand Box mode would go a lot of good for new players... say one box with 10 hp another with 100 and another with 1000000000 would let them have a little fun seeing how thier units fire thier weapons since that is a big thing to understand in CA / 0-K

Also having a big target with a lot of HP will spark an ambision to grow enough to be able to deal enough dmg to kill it. The Boxes should respawn after death for continued use.

This would make the sand box be probably 2x more sand boxy. :)

How about a Big Red Button that says "Click here to spawn some enemies" ?

I gave missions a stab earlier but was not too successful with the new mission syntax.