Pros:

Awesome environments
Who would have thought that the Mario theme would work so well in a zombie game?

Cons:

Bots are too stupid for this campaign
The fireball part can be kinda tricky
I expected more out of the finale

Conclusion:

Ah man, great work! It really looks and feels like you're playing in Mario's world. It's well-paced, and pretty fun throughout. The only con I'll elaborate on is the finale. It's a small area with no safe spots...and I just don't like having to do a 360 degree battle all the time. But climbing the plant to get out was a great idea :)