Not the best TD
I really do like TDs but this is not the top of the heap. Autosave is nice, thanks for that. Difficulty levels: kudos. It's pretty, that's nice. That's where the wonderful things about this game end though. It's slow with a capital S/ Now, my computer isn't very fast, but it runs much more complex flash games significantly quicker. It feels like you sacrificed elegance in coding for little sparkly things in the river and pointless animations in the little supply carts. Please don't do that. I don't care if the river is sparkly, and I doubt most players will.
You start out with only two weapons and no ability to build defenders in them. The strategy at this point is laughably easy. It doesn't really matter which you pick, probably, but it's better by far to stick with one type of tower, since you upgrade all the towers of a type at once. Also, why have us pay for upgrading and then pay more for the upgraded towers as well? Actually, the more I played, that aspect grew on me. It adds a little strategy in that it's best to place as many towers as possible before upgrading while still holding off the enemy.
Y'know, it's not a bad game at all, but the major drawbacks are the slowitude and lack of an interesting challenge (note to future reviewers who will say 'try it on hard and then say it lacks challenge,' I played on medium, and 'interesting' is the key word).
I didn't find this game very enjoyable.