Pros:

+ Simple, yet mazelike, level design is great.
+ Smaller campaign makes for quick runs with friends who don't want to spend two hours playing.
+ Swamp looks better than Valve's.

Cons:

- Lack of ammo piles.
- Lack of melee weapons.
- Last map was short, so we wondered why it was even added.
- Breezy finale. 
- Infinite bile bombs at the finale.
- Had pretty much every tank spawn outside the game zone.

Conclusion:

I get that this is still a work in progress, but some issues are just... Too big to go unnoticed. This campaign has potential, but in it's current state it is too buggy for there to be an open beta. 

Good luck!