Boxhead: The Zombie Wars
Boxhead, that zombie shooting series has it's fifth game out and this one just keeps getting tougher and better. In Zombie Wars, you have more weapons, more zombies, more of everything waiting for you in this shooter.
This game is tough. The number of zombies quickly gets out of hand. You need to learn how to react quickly, strategize (barrels, barricades, etc...) and more within the first few levels or else you will be dead and buried before you know it.
There are plenty of battlefields to choose from, but it all comes down to your reaction time.
Play Boxhead: the Zombie Wars at kongregate.
Update: Now that I've played this game for a few weeks, I have a few pointers and tips. First, the basics.
There are two scenarios as you start out. On the left side is the basic, and on the right side is defense. They are the same game, it's just the 'defense' is how things should look for you after a five or six rounds (if only a little bit neater). You have a defense set up, with turrets and barricades. You also have access to some more weaponry (as if you had worked your way through the earlier rounds).
The difficulty ratings also place you further along. It's as if you start off at round 10, instead of round 1. You have access to more weapons, but the demons are already out to get you. So if you're a newbie, place at beginner until you can get past the first few rounds. Then up the difficulty. It's as if you're restarting at a later level.
Scenarios. The scenarios don't really matter all that much to me. Different landscape doesn't really affect gameplay all that much. The smaller the field, the faster you have to deal with the hordes that come upon you. Also, you don't want to get trapped behind your defensive bulwarks, so the direction they come at you isn't all that important either.
Basic walkthrough strategy: Set up a defensive perimeter using turrets and barricades. Place more turrets and barricades as you can. Replace those that fall. Other than that, stay outside of your own perimeter and blast away. If you stop for even a moment, the devils will flame you to death. It only takes two quick shots from them to finish you off. Plus, you need to get out there and pick up the boxes to restock and replace your health. With a good defensive perimeter, you can last for a very long time. Once I have a good setup going, the only reason I lose is because I end up setting turrets around myself, trapping myself.
Barrel laying is great. If you start laying out barrels in a trail behind you and set them off (or they get set off by the turrets or by the devils), you can lay waste to hordes at a time. It's also great as a more offensive weapon. Once the barrels are placed behind you, they can set off the next one in line (sort of like dominoes). If you keep running ahead and placing more barrels, you can basically charge into a crowd and clear them out with explosions.
The minigun is great at clearing out a line, but I find it hard to select it. Instead, I usually use the barrels then the shotgun (once it's been sufficiently upgraded). The air strike is fun (it will clear the whole screen). The handgun is actually quite useful for a while, but won't help once it becomes too crowded.