TOP 3 Minimum Standard Weapons: Please note that my criteria for saying these are the top weapons are the following: 1. Versatility and Useabilty; 2. Overall specs (compared to price); 3. Availability (minimum/low glu gold requirement)
1. ZRU-12 Advanced - The best SMG I have used and is still the minimum SMG that I will use in any mission. Overall stats, particularly rate of fire and ammo capacity, makes this weapon a great one to use. The difference with this to the standard ZRU-12 is just the killing power. In CKZ1, the best affordable SMG is the 9mm Technic. In CKZ2, the honor goes to the ZRU-12 (if you get it discounted through the 77 glu weapon package)
2. Rontron Sniper Rifle - Even after getting the Demo X400 or Boarles .50, this is still a best friend in survival missions. By the time most zombies reach the base, they are already dead with one shot to the body or head. Use this to kill Throwers, Bombers and Pipers. Kill Smashers with at least two reloads (8 shots per reload). For a price of 60 gold, it is worth buying. While you don't have this yet, you can settle for the Commando Elite but the catch is that you only have 4 shots per load and it takes a few more shots to kill the security zombie.
3. Dual MP-643 - High rate of fire with large ammo capacity makes this a useful weapon to keep common zombies at bay during escort and supply missions. This is a good backup weapon when your assault rifle is out of ammo. Get it discounted through the 77 glu weapon package. If this weapon is still beyond reach, you can settle for the cash-based Block-19 (a lower version of the Desert Hawk)
TOP 3 Best Overall Weapons - Makes zombie missions a walk in the park and only in very extreme cases will you need to use a medikit or defibulator.
1. Streetsweeper Auto Shotgun - Other than special zombies, you will never fear a horde of common/security/scientist zombies once you have this weapon. Imagine "Plants vs Zombies". This weapon is the ‘lawnmower” and it literally clears the path for you.
The downside is that it is a bit expensive but still worth getting. I suggest taking advantage of any discounts that the game would offer for this weapon.
2. C16 Auto Assault Rifle or .30 Light Machinegun - For those who already have the Mortara, you would not even bother using these weapons. But since the Mortara is one expensive weapon, I consider these are two alternatives (one gold-based and one cash-based). If you are not facing special zombies, these are perfect additions to your arsenal.
At close to medium range, they have the same effect as the Streetsweeper. So how are they different? Only in terms of cost, ammo capacity and damage. Overall, they are both good weapons.
3. Annihilator or Exterminator - I know both are expensive but you really need to invest in a grenade launcher. There will definitely be stages where you need to kill the special zombie quickly, and a grenade launcher is a perfect solution. If you were able to get the discounted Annihilator at 500 glu gold, call yourself lucky and start using it.
Otherwise, here is one alternative: Widowmaker K-13 with damage boosts (1-2 shots would kill most special zombies easily).
Comments and feedback welcome. Opinions on the list may vary. Even without gold-based weapons, you can finish missions with enough luck and skill.
The Wolf Pack are my friends, like all others whom I have the pleasure to know. You have my respect because you deserve it - the same way I expect this respect from you as well.