AI issues don't ruin a great TD.
The fundamentals are solid, the graphics great, and a good tileset. I appreciate the minor things like decals on the ends of walls, the fact that towers "mesh" together, etc.
The towers get the job done well. In fact, almost too well. For pretty much the first 2 levels, I never even touched the Elementals.
However, the Main concern is the AI. It isn't intuitive enough to prioritize attacks. For example, sometimes the enemy will just rush to your HQ, completely disregarding the towers/ walls. Other times, it will attack the walls, and completely miss the tower; regardless of the fact that there is an open path to the towers; and sometimes the AI is spot on.
That being said, I'ts not too bad of a flaw, and after making plenty of Tower Defenses back in the glory days of Starcraft, I know how difficult it can be to mainpulate the creeps.
In conclusion, you get a 9/10, for thhe overall experience was fun, and it ate up 330 to 60 minutes of my time in a blink of an eye.
(One More Thing: Release a Map Editor, or something else to enhance re playability.)
A tip for players: Fortify your towers with walls on the outside of the tower, don't put towers in your wall segments, or infront of them. This will force the creeps to attack your much more fortified walls rather then your more expensive, weaker towers.