While the core mechanics of Atom Zombie Smasher are easy to understand, they can be hard to master. Should you wish to play the game with a lessened challenge for maximum zombie smashing fun, simply follow the instructions given hereafter.

So you've started the game. Should you not have the great fortune to currently have two friends in the room who would like to join in the zombie fun, simply open up the options menu and add two controller players. They don't actually have to do anything for you to get the achievement. Just be sure to keep the extra 'players' around while you smash zombies in the campaign.

Your new campaign should be setup as seen below:
Make sure to choose the extended game. With the addons checked, you will want the extra gametime to be able to use your mercs. The first four make sure you get a large and well equipped set of mercenaries, casual keeps the zombies slowed down and less ready to shamble into your civilians, while triplets lets you have three of a given kind of mercenary. Lastly, chooser lets you pick your squad, even going so far as letting you drop the helicopter as unnecessary. While some of the achievements require judicious use of the helicopter (see rescuing 100 people in July), most of the long term achieves require cumulative focused kills from each type of merc, or an exceptional number of kills from a single merc in a level.

NOTE: Using the setup shown above should make winning any level, regardless of the infection level, ridiculously easy once you understand the mechanics. Should you want a greater challenge, disengage triplets (requiring greater variation in merc composition) or enable alt spawning (allowing zombies to enter inside the city, not from the edges).

Should you be new to the game, the easiest mercs to use are, by far, snipers. The infantry units are also quite useful. Remember, we want to accumulate kills on our mercenaries, so be sure to unequip the helicopter. The mercenaries will also gain xp for every zombie they kill. Focus sniper upgrades on decreased reloading time, since if you have properly positioned them with line of sight, you should not need to reposition. For the infantry, focus on upgrading accuracy to ensure efficient zombie death. Once your units all hit level 3 you will steamroll any enemy.

To ensure maximum zombie destruction, be sure to use your saved scientists for two main upgrades. Increase the xp gained my the mercs for each zombie kill, and buy one upgrade to the total llama bomb count. Should you pick well clustered regions for your llama bomb when they come up, you can easily decimate the enemies' regions. I have in some cases cleared the entire map, resulting in a five scientist bonus for that week.

The key to achieving lies in regular, constant, continuous wins over the zombies. With each win you will have a chance to have one of the bonus clips pop up. Once all 20 of these randomly unlock, you will receive an achievement. Your uncompromising force and continually increasing wave of saved regions will rapidly accumulate you points, such that the difference between the medium game of 6000 and the long game of 20000 is much shorter than the point values would imply.

Be sure to mix it up. Once you have a core group of mercs, try picking a single extra unit of a type you rarely use (dynamite, perhaps?) and letting it get a few kills before mopping up. Achieving the "many kills for one unit" with offensive types is as simple as placing everything but the one unit poorly, then putting all the effort into just getting the kills. You may lose one map as a result, but as previously emphasized you will steamroll the zombies. A loss for this achievement is minor.

Most of all, have fun. I tend to have more fun with this game when I run roughshod over the zombies, but for you a tense game without these addons could be just what you were looking for. Try out some combinations and see what works best for you. More than anything, proper placement of mercs and wise use of scientists will carry the day, no matter the setting you use.

Unlike the other mode, the key here is to keep ≥1 person unzombified. In other words, feel free to sacrifice nearly the entire map, so long as your designated person stays alive. You can most easily kill the zombies while they are within your hovering circle, move to get close, then shoot. Make sure to get each upgrade, and save them for the later waves. The super zombies will eventually spawn, and you need to use the consumables to down them. Be most careful in early waves. Due to the population density near the beginning, a single bite could ripple through most of the people, resulting in too large an infection to put down in time (resulting in a loss). Keep it under control, but be sure to let some groups get bitten early to keep your safe group isolated from harm.