Tesla tower. Beacouse COILS. The TESLA coils... The coils of NIKOLA Tesla.

Attack is far and away the best module. Get them to rank 3+ and you can hold almost any choke pretty easily with half decent heros. I don't understand why you would need them to affect more than just the heroes in the room they're in to be worth it. They're not that expensive and the bonus is huge. If they worked no matter where you were it would be ludicrously overpowered to drop them everywhere.

they look awesome on rank 4 xD

I'd never upgrade a science module. I never build any science modules, so why upgrade them

Hud if I can get it. It completely replaces any suppressive fire modules allowing more Dust Field or Autodoc Crystals in your choke points. It can also be boosted by a weaker hero who doesn't do well in combat. Even with 7 wit, the level 1 bonus goes from 18% to 40%



Food is a good one, but falls short of this due to the fact that it's often easier and more effective just to man your modules than upgrade them. Seriously, for 137 science you only double your resource levels in one area. Upgrading any FIDS generator is kinda weak right now.



LAN is also nice. If you have a choke point with a major module, a LAN can save you many resources on rebuilding should you decide to use the major. If you have beachheads to weaken incoming forces to your choke, a LAN can help them hold out long enough against the zombies to finish them off. If I could choose 2 options, LAN would be my second.



Prisoner pods I'm not fond of. Sure they are less than half the price of a tesla, but the low damage is easily ignored by mobs. Why not just arm your heroes with feather dusters?



Dust Fields can be stacked for immense armor boosting. Gort in a Arrrr Suit with 4 Mk 4 dust fields will have 300ish armor. This makes him able to take punishment you've never imagined, and when he's level 8 he'll really let loose.



Autodoc shards can also be stacked, and furthermore they can be stacked with Dust Fields. This greatly improves their healing ability. Same situation as before with Gort and he'll never die, even with 50 mobs in the same room. I've done it, I know.



Suppressive fire you should replace with HUD as soon as you get it. This allows you to be even more flexible with your layouts.



Mortars and Tesla coils are both very useful. Place mortars out in beach heads and tesla coils in the next room. The mortars get to enjoy a target rich environment, while the tesla coils quickly pick off any weakened targets that make it through. 3 Tesla coils also cost less than 2 mortars, so you're saving on resoures for an undefended choke point. Just remember to repair it every wave. I hope you have a LAN too.



Tear Gas is only really useful if you have to use prisoner pods. That's the only way to really overcome late game armor with prisoner pods. If the game has trolled you and left you without mortars or tesla coils, then grab this, otherwise pass.



Neurostun Modules are very useful on mortar beacheads to slow the progress of enemies passing through as well as bunching them up. 3 mortars and a neuro stun kill almost all targets passing through where 4 mortars would not. Very useful if you are looking at unmanned defenses.