X-Com: Enemy Within Heavy Build Guide
The Heavy class gets the big guns and the big grenades. When you really just need to shoot bullets in a general direction without much concern for collateral damage, then the Heavy is your go-to guy.
The soldier gets to fire a rocket once per mission. They can't move before the shot and they will need line of sight, unlike grenades, but the shot goes farther and does a little more damage than the grenade. The Fire Rocket ability is a critical ability for the Heavy. Whenever you want to reach out and touch an enemy with weapons of the explosive nature, the Rocket is your weapon of choice. It gets pretty difficult in the heat of battle to get a group of baddies in the same place to pose for your explosives, unless you have a Sniper with the battle scanner ability. You can drop the scanners and the spawn point won't scatter like it normally does when you first find them, leaving you with a perfect grouping for explosives.
This is, honestly, my favorite ability for the Heavy. The simplest use of this ability lets you shoot twice in a turn. Great for putting your biggest gun on the same target twice or spreading the wealth to multiple enemies in the same turn. A more advanced use of the ability will allow you to shoot, then move. Normally your turn always ends as soon as you have fired your weapon.
This ability essentially "lights up" the target. Any enemy that you suppress or fire at on a turn will have a +10% bonus applied to any other allies firing at him in the same round. This can be good for taking down a big or hard to kill enemy, however it's rare that the Heavy can't kill a big target with two shots that Bullet Swarm could have given him instead of this ability.
For the next four turns, any enemies hit by this rocket suffer 33% more damage from all sources. The best part about this rocket is that it's a four damage rocket, instead of the six damage that the Squaddie level rocket gives you. This allows you the option of shooting a weaker rocket that may not kill your enemies, but instead give you a solid opportunity to capture or kill them with regular gunfire and loot their corpses.
Suppression picks a target and reduces their aim by 30. Your soldier will also get an opportunity to fire on them, just like Overwatch, if they move. This can be used to pin down a powerful enemy that you can't hit easily. Suppression will also remove the targets reaction shots, making it safe for your troops to manuever on the battlefield. Combine this with the +10% from Holo-targeting and you can take an enemy from an incredible defensive position to a dead position.
This ability simply gives a straight +50% damage against robotic enemies. This is a step down from the +100% it used to have in Enemy Unknown. This is likely because robotic enemies have become more prevalent with the Seeker showing up early in the game and the Mechtoid showing up a little later. Considering that most of the robotic enemies got a little bit of an upgrade on how hard they are to damage, HEAT Ammo could really pay off.
Rapid Reaction allows your Heavy to shoot two reaction shots in a turn as long as the first shot hits. This will usually allow him to hit one target twice on the enemy turn. All the more reason to give your Heavy a SCOPE. Be careful though. You could empty your weapon shooting down a useless drone and then be on empty the same turn a cyberdisc is sitting in your Heavy's face.
This one allows the Heavy to pack two grenades in a single inventory slot. In addition, the Frag, Alien, and the new Needle grenades all get +1 damage, making an Alien Grenade almost as powerful as a rocket. With the new Tactical Rigging project in the Foundry, your heavy will be able to carry four grenades into combat.
Your Areas of Effect on Suppression and Rocket attacks are increased by two tiles. This can be a benefit and a loss. It's great to be able to hit so many aliens in one shot. The downside is that it gets a little harder to position the AOE where it doesn't hit any of your troops. Sometimes, a surgically placed rocket is the best. It doesn't increase the AOE on grenades, so you can toss those in when a rocket blast is to big, if you are close enough.
Will to Survive
The Major ability on nearly all the soldiers is incredibly defensive. Will to Survive is no different. It seems pretty simple at first, but the benefits are priceless. It reduces the damage taken by the Heavy by two as long as they are under cover and not flanked. This even applies to critical hits. As long as your Heavy isn't flanked, he can draw the attention of several enemies without having to fear several high damage shots in a row.
The Heavy will gain a second rocket to use by taking this ability. If you already took a shredder rocket, you could have three rockets on a mission. Add Grenadier if you want to be loaded with explosives on a mission or take Danger Zone to create a huge AOE for all three rockets you have (and should be firing if you have them) on every mission.
Mayhem adds a damage bonus to all AOE abilities, including Suppression. This bonus gets better as your weapon technology gets better. By this point, a Heavy with a Heavy Plasma weapon should be just as dangerous as a Sniper with the Plasma Sniper rifle and if you made the right choices, both of them could be shooting twice a round!