Was fun.
I quite liked it. Although I do wish the base played more of a role then just being a 2nd health bar.
The base should have been able to do damage to zombies that got near enough to it.
That and everything was so expencive you would have to play for a long while to get enjoying it, what with the reloads being slow to start and not doing much damage, the only reloading tactic was to hold your last round and switch to another weapon, but once they all ran out you were pretty much waiting to reload and certainly suffering damage to both healthbars.