This is the game has almost all the things I would like to put in "my game"... but it lacks LOT of other things I would add.
How's that possible?
On one hand, you have a, let's call it "XCom light" part of the game: Survivor management let you equip your squad with different weapons, equipment (Which you will built with scavenged supplies) and make them better at different skills. Then you can send them off to dangerous missions to scavenge more supplies and try to learn what happened to the world.
You go to several random-generated maps and explore the houses: You can find supplies, places to create new bases (And get more supplies), bombs which will detonate if you don't find a wire cutter, alarms... all of them really helps to add variety to the game.
The action (And the inclusion of the dynamic pause, like in Baldur's Gate) feels quite right (although I would liked to have the classic "stand ground/patrol/look only in this direction" buttons). It let you order your survivors move around and maybe only will get you in trouble if you go too fast.
But, on the other hand, there's not really so much content
All the places loolks horribly similar. The random generator picks two-three houses from a set of pre-made maps, the street its just empty. All the characters look the same and have almost the same voice. Even the special zombies are all out from Left 4 Dead: You got the spitter, a charger's cousin, and smoker... and of course you need another survivor to rescue him. Still, they work good in the game (hey, they are proven formulas).
Even the inclusion of events (like the bombs, the hordes or the attack) fall short and after some maps you have already seen everything (In almost every single combination that matters).
There's a lot of good ideas on the game, fairly well implemented, but the general feeling is austere, lacking of both more content graphically and gameplay wise. Maybe you will have to rethink your strategy once or twice but after realizing that sound matters and guns don't, you will be set up to the final boss.
Its a feeling of "yeah, that's right, I want MORE. And maybe some tweaks on this, and more equipment, and different survivors and..." it's something difficult to critizice, given its indie development, but still, there's a sensation of "we couldn't add fancy stuff to the game" after the second map that just don't go away.
I haven't played the lab mode, by the way, only the campaign.