Interesting
It's a good game to play although you should have some of the guns locked ans slowly open more guns through each level you unlock. So level one should have say up to the "flak gun" unlocked. Don't show what the other guns are untill you beat the first level. Then when the first level is beaten. A screen could say " congratulations, you have beaten the first level and unlocked the "plasma gun" and then you beat the second level and at the end of that level it might say " congratulations, you have beaten the second level and unlocked the " missile tower". and so on. So you need to have about 20 towers to unlock instead of the 8 you only have. Also maybe on the first level you can only upgrade towers once and the second level can let you upgrade the towers 3 times. and wait till about level 4 and you can upgrade towers 4 times. So you need to have a good upgrading system that can upgrade 4 times.
So that's my little peace. But it is a good starter and the functions of the guns are nice and look good too.
777overload