This game is pretty easy if you max out the right upgrades. As long as you mana skills are top and you max out your orange gems. All I do is make orange gems and orange gems only. On the last level I fill the path with orange gem traps and watch the mana come pouring in.
It took me a little bit to figure out what I was doing wrong on the later levels, but once I started putting the restaurant in the front and making it my lowest priority, it got easier. The food store just plain stinks but at least it slows people down at first. Overall I liked the game 4/5
My only complaint is once you have a maxed tank, your done. I picked the mitosis drone tank. Didn't really like it. Tried to get hit to drop a level, and then pick something else, but everytime I get enough bubbs, back to mitosis.
I really wanted to like this game, I liked the oil tower/meat thing going, but the accuracy of the towers is so bad I had to change my original rating to 2/5. I watched a slow moving enemy (bear) pass by like five towers and not take any damage when it only had like 2hp left. That aspect alone makes this game worthless.
I got the same thing as HeebyJeeby. As soon as you upgrade past the 400-500 mana cost items, you can't upgrade even if you have the mana. At least the mana pool upgrade will say maxxed out, but the rest list bogus requirements (960 mana) that never let you select them.