I eh... it doesn't seem to be much beyond a concept that's for sure. Are you looking for suggestions as to what to do next?
Well, it seems to be a missile command game on its side,yeah? i don't know what advice to give. I'm sure you are gonna add, statistics, goals, maybe a score, some audio, updated graphics and some fun surprises here and there?
The word "Defense" in a game title these days leads people to believe its a "tower defense" type game where you set up turrets, etc. No reason that can't work but there doesn't seem to be a hint of it in your game, so consider revising, maybe once more mechanics are stabilized.
and wouldn't it be neat if this had something to do with DNA even if completely fictional? Maybe some kind of bizarre protein that is trying to destroy the DNA or alter the makeup to create something else. At least there you have a win/fail state.