Seed of Destruction is today's epic game. What's more epic than a cowboy riding around on a sperm cell? I give this an 8/10 on the epic scale.
Level 1: Just ram some people close to the ground, since that's all there is to attack. (Score 500 points for next level)
Level 2: Make sure you dodge the attacks of the helicopters (I found it best just to ram into them), as well as attack some people below. (Score 6,000 points for next level)
Level 3: Same as before, but now there's jets and army soldiers. To get the jets, get one to follow you, and bust a sudden u-turn to ram him. Make sure you avoid the bazookas in the process of this. (Score 20,000 points for next level)
Level 4: I just hovered around the top-most part and deflected down grenades/missles while defeating airborne enemies. Since you can't destroy tanks from up close, getting them from a distance is the best bet.. (Score 50,000 points for next level)
Level 5: I found it easy just to go off-screen and make the zeppelin hit itself. After destroying a few of those, you'll have the achievement in no time.