Mecha Design in GearHead Caramel has significant differences compared to GearHead 1 and 2.
In GearHead 1 and 2, the ultimate target would be to up your Initiative, then design a flying Savin (with lightweight Condor wings) with as many Breaker Cannons and/or Phase Cannons as you could put on hands and mount points without dropping the mecha below 0MV/0TR. Because each weapon refreshes independently of others, having multiple weapons was needed so you could fire continuously on every turn you got.
In GearHead Caramel, however, the combat system is unaffected by Speed or Initiative. You get two moves for each turn, and each mecha gets one turn per round - Initiative and Speed matter only for the order in which each mecha gets a turn, but everyone gets turns at the same rate. This changes your priorities in designing mecha.
Melee[]
In GearHead 1 and 2, you simply do not bother with melee weapons. Phase Cannons can shoot from one end of the map to the other end, and no mecha is fast enough to engage in melee before a flying Savin with 6 Phase Cannons has taken enough potshots at it to take it down.
The scale of combat is changed in GearHead Caramel. A speed-optimized mecha can spend one move (of the two moves it gets per turn) halving the range of the longest-ranged weapons in the game. A successful cast of Stealth can hide your mecha, preventing it from being targeted, until it is near enough to attack in melee.
However, what really changes things is the Charge Attack attribute on some melee weapons. With a Charge Attack, a mecha can move closer and perform an attack as a single move (of the two it gets in the turn); the only requirement is that there can be no other mechas or other props between itself and its target. Optimize your mecha for movement speed and you can quickly close with even the longest-ranged mecha. Charge even gives an accuracy and damage bonus.
Every melee mecha should have a weapon with Charge attack. Below are the top Charge Attack weapons as of this writing:
- Iron Lance - Salvaged from the Iron variant of the Dielancer. One damage level higher than Giant Drill.
- Giant Drill - Can be purchased from any shop, but only pops up rarely.
- Ion Lance - Low damage compared to the above, but HAYWIRE OVERLOAD. Get one from the ordinary Dielancer variant.
- Plasma Lance - Comes on every Joust. Start with a Joust, or buy one (it's cheap, you can afford one after doing Osmund's mission). Good early in the game, replace with the above weapons as soon as you can acquire them.
Most Charge Attack weapons have a low accuracy but high penetration, which is good against heavily-armored opponents, but bad against lightly-armored nimble opponents with good mobility. You'd still want to use Charge Attack to quickly close with a high-mobility opponent and get a free (if low) chance to damage them, but once in melee range you should switch to a high-accuracy low-penetration melee weapon such as the Mecha Sword or Heat Axe.
Most melee weapons are 4 slots or less (the Ion Lance is 8 slots, though). This generally means you can remove the hands of your mecha and mount the melee weapon directly into the arm, and if you can acquire armor of appropriate size even beef up the armor of the arm. Removing the hands shaves off 0.5 tons from your weight, and unlike in previous games, installed and mounted equipment has equal effect on your ability to avoid damage. Melee mecha only really need two weapons: a charge weapon and a backup high-accuracy melee weapon (though an Intercept weapon would be good to install in the torso as well if you have space and weight), so you can also strip off any mount points elsewhere to shave off more weight, which helps your raw movement speed and your ability to dodge attacks. You can upgrade engines in GearHead Caramel, and you might actually prefer to remove higher-level engines from a larger mecha and install it into a smaller and lighter melee mecha for the improved evasion.
Wheels are best for raw speed, which effectively determines the reach of your Charge Attack. Wheels give more dpr than Hover Jets of the same size, and are half the weight as well. A Corsair is generally a good base for a melee charging mecha, due to the wheels it has coming out of the factory; the Dielancer is an example of a modified Corsair that takes this melee charging paradigm.
With high speed, you can "bounce" off the front-line mecha of your opponent, then reach the backliners, without suffering "Too Far" or "Sensor Range" accuracy penalties that ranged mecha would have.
Shields add an accuracy penalty on all weapons on the arm that is carrying it, and are generally weighty as well (hurting your ability to just evade the attack), so it's probably not worth putting shields on your melee mecha, even if blocking with shields uses the same skill as melee combat. Though melee weapons are generally small enough that you could try putting both your melee weapons on a single arm and wield the shield on the other arm; while losing the arm with the melee weapons makes you weaponless, if the pilot has Repair skill they can recover the use of the arm if they have sufficient Mental points.
Assault[]
In previous GearHead games a mecha with 6 Phase Cannons piloted by a character that gets initiative faster than those weapons can reload was your ultimate goal. However, with the changed rules in Caramel, getting multiple of one type of weapon is generally no longer good advice: getting two Phase Cannons simply means you have a backup in case one gets destroyed, but doesn't let you increase your DPS. Instead, getting another weapon with different accuracy/penetration tradeoffs is generally a better option.
However, certain weapons have the Linked Fire attribute. If you have two or more of the same Linked Fire weapon on the same mecha, you can spend Mental points to fire them at the same time, to potentially two different targets. If you can get enough of them, you can get 4 or more weapons firing in a single move.
While the attribute does let you scale DPS according to how many of that weapon you can cram in a single mecha, the Mental cost is usually too prohibitive for you to keep this up for an entire mission. However, arguably the purpose of Linked Fire is less about the raw damage-dealing, but instead about overwhelming your opponent.
In GearHead Caramel, the overwhelm mechanic means that, when a mecha is attacked, future attacks get a +3 accuracy bonus. Every time a mecha is attacked, an additional +3 accuracy bonus is added, even if the attack missed. Doing a 4-weapon Linked Fire on a single mecha gives a +12 accuracy bonus, since the mecha was attacked 4 times, and you do this with only one move in your turn. Your other lancemates can now hit that mecha much more easily. So generally, you will use normal attack most of the time, but once you have to mop up a nimble mecha hiding in cover, you can unleash Linked Fire on it so your entire lance can hit it more easily.
Generally that means removing or reducing the armor in your arms, then installing Linked Fire weapons on the arm directly (most of the nice Linked Fire weapons are just 4 slots) and if you can get even more weapons, install hands and/or mount points. Your arms will be very vulnerable due to lacking decent armor, but when you unleash Linked Fire you can be firing up to 8 weapons at the same time on a single target for a whopping +24 accuracy bonus every other ally will gain against that opponent.
The pilot of such an assault mecha need not have good Mecha Gunnery or Reflexes/Perception. Instead the pilot has to have good Speed (so it is likely that he or she or zey will move first before the rest of your lance, so that the rest of your lance gets the benefit of increased accuracy), and good Ego and Concentration (to fuel the high Mental cost). Good Mecha Piloting would also be nice to protect your lightly-armored arms.
A possibility would be to install a high-damage low-accuracy weapon as well, such as a Heavy Gauss Rifle; consider how the Nova Storm Buru Buru is set up, with two Linked Fire Stomr Pistols and a single powerful Nova Cannon. Linked Fire to overwhelm the opponent, then hit with the low-accuracy high-damage weapon However, the weight might be too much for a single mecha if you go for large numbers of Linked Fire weapons, especially since you are likely to sacrifice armor and mobility for weapons.