The game is pretty short so you make multiple runs unlocking characters, weapons, and upgrades each time. In the beginning your soldiers are not very strong so you'll die a few times. Once you build some power you should win each run and open up new stuff to make it more fun each time. The game is very tactical. Cover, range, and reloads all matter. I had very few bugs or glitches and they were very minor. My favorite soldiers were the cat, dog and rhino but you should try them all because they all have different abilities.
I am giving 5 stars not because the game is perfect, just because I'm having so much fun with it. There is room for improvement, but I played the campaign through twice and am happily starting a third run through. The first time through I followed the good path and the second I stayed on the dark path. The endings were dramatically different. There are a couple more story line choices to try out and we'll see if there are other endings. Then I'll give free mode or conquest mode a shot.