Pros:

Half Life 2 Materials and Models
Concept of Interaction
Lots to Explore

Cons:

Bugs... Bugs Everywhere.
We got caught on the generator where we couldn't move and our guns were invisible. We almost got killed by Zombies.
Not a lot of direction on where to go and what to do without searching deep.

Conclusion:

Too many problems for me to enjoy it sadly.

Pros:

Good Charger practice.
Fun to replay.
Easy to use.

Cons:

Sets of Chargers has a small waiting period.
Bit difficult to deal with Tanks and tons of Chargers.

Conclusion:

Not much else to say, I like it.