I really like the base idea, reminds me of the Starship Troopers series! Some control over the units would be nice in the future! I was playing the we build, and units stopped from time to time, even tough they were in friendly territory. This caused a few troubles. Let them just move forward even if slowly.
Sounds are nice, but waaay to loud on normal sound levels, please check it next time before publishing!
Other thing I was missing (probably because of the time ran out) is the bullets! Would lift the whole gameplay experience up!
Overall well made, just needs a few tweaks!