The headshot achievement is made almost too difficult by the fact that the game has fairly poor aiming. Especially obvious at the end with the soldiers.
I managed to break it trying to get past granny. Jumped on counter then hit blender right after. Left the blender on and left me with only the air conditioner switch and the dog to click on.
Cleric != Priest
If you are familiar with D&D at all, clerics in it wear heavy armor. And seeing as D&D is a popular thing to base stuff like this off of...
Main problem I have: You can outrun your own shots. Your shots move the same speed no matter if you're shooting in the same direction as your motion. Doesn't exactly make sense. As such, the easiest way to play is to simply move opposite to the direction you're firing.
Actually, I managed to beat the final mission and the ones before it by mainly using the dual machine gun and a shield. I simply saved upgrade points to upgrade the machine guns damage and got a damage buff, and had it doing 3 damage a shot (or 5 if I managed to get another upgrade). Of course, I had to use the heavy cannon in order to destroy the wall guys.
I suppose I'd give this game a 3/5. The graphics leave something to be desired, and the towers seem a bit lackluster (plagiarized even, descriptions and numbers for them are almost the exact same as Burbenog TD, and I saw no credits). And the new 'paths' are easily predictable, being predetermined, though they can ruin your game far too easily if you don't know where they are. Ah well.