Any "lag" you experience comes from your own computer's fault. Not the games. This game does not deserve a bad rating based on that! However, I do think the difficulty curve should be evened out a little more. Between the red crosses, and the triangles, I can't last too long.
What the hell? there's chain posting now. Lol. Good game! I wish there was more of a story line, and possibly more buildings. One of the best Kongregate games to date though! Seems more like a RTS game than a TD game