A good game of Horde can take 2-3 hours and you not rewarded with enough coins for such a long grind. My only complaint is the reward rate for 'coins' to spend on upgrades is way too low. I have played Horde a little bit and may even keep the game around to play multi-player after completing the campaign (which is something I've never done before).
I completed the campaign last night and quite liked it.
