pretty decent
i liked this game, but there are alot of flaws,
-the game was too hard, i got to lvl 31 of the first map, and then i died.
-the maps last too long, about 20 waves a map is plenty.
-the factory system has alot of glitches, i had to build 35 factory's to get the last tank while it said 24(or 21, dunno anymore)
-starting at the red tanks, the tanks can go through your tanks and both survive with a small amount of health.
-the upgrading takes too long.
try to fix that and you have a great defense game