Very enjoyable but...
... perhaps it is too challenging. I think the first level was excellent, I thoroughly enjoyed it, especially as it had good length. On the second level however, I don't think you get enough time to build turrets. The vehicles are very quick and I myself couldn't do it. If it were a little easier I would've loved it even more. The graphics were very good and I enjoyed the level layouts and from what I played the available defence. Still, I think you could've done better but I can't say it's not a fun game.