too difficult
Too difficult. It took me three tries to beat it on easy. That's not what "easy" means imo.
Improvement: The color upgrade wheel should allow you to see what it is the later upgrades do (the ones that you haven't unlocked yet). I wanted the sniper tower but I went the wrong way since there was no way to know which end segment was the sniper until you've upgraded the two under it.
Graphics were very nice.
Sount was not good. Some of the towers firing sound effects were just... well.. lame. Especially the sniper tower. Also the graphic of the sniper tower's projectile was kind of lame as well.