Beats the hell outta the first one!
You can also unlock special drawers, weapons and power-ups. Although you could do this in the first game, in Army of Zin you can keep them on file and change your atributes on the fly.
Plus....you get to play as Grimm! When your power meter is full, you can become invincible and play as Grimm (Reaper) for a short time. The graphics are still quality, and the story is a direct continuation from the first one.
It's cheap enough; give it a try.
-B