I personally don't like it. I don't feel like its a tower defense game.
You place your guns at the end of a road that basically has 5 lanes and the enemy walk down the road and if they get close enough they damage your guns. You can repair them by upgrading them. I've only unlocked the first 3 guns/ towers but found the gameplay very boring and I won't be playing anymore. I'm not the best person to take advice from because I am a picky person but I personally don't think this game is going to do well with many people