@Reton8 Sure, why not(long post alert)
A lot of the scenarios look very much the same after a while, so the general strategy remains similar. Technically, there's more than these game modes, but everything plays the same after a while
*Kill the other team off - this applies to anything where you get your cool weapons to kill the enemy - e.g death match, point capture, etc. These are pretty straightforward - just be good at combat and you'll typically win easily.
*Capture the flag - Combat isn't very important here. You just need to be able to run in and capture the flag. Most of the scenario is just spent walking around. if possible, wait until the flag area is clear before grabbing the flag. The AI is stupid, and tends to fall into chasms(possibly to their death), so it's very hard to lose.
*Gun game. These kind of suck because they are usually ruled by level. Unfortunately, you'll be heavily underleveled for most of the campaign unless you utilize AFK grind, which requires you to outpower the enemy.
Starting Off
You start with only one engineer(Nathan), and can soon hire a second gunslinger. Hire him ASAP, and I recommend using him. Even though it makes deathmatches and the like a little harder to win, these matches are relatively easy at this point, and you can afford to let that happen. You'll probably be able to beat all the scenarios handily except for the Doctors of Doom scenario. Pass on that one. Before long, you'll start seeing expanded unit caps. Hiring heroes is pretty cheap, so it may not be bad to do so, even if all of your heroes will be gunslingers and engineers.
Mid game
As you advance, you'll unlock more hero options. In order, they are: Engineer, Gunslinger, Medic, Juggernaut, Sniper, Ninja, Merc, and Elite (there may be some inaccuracies as I sold some of my heroes). You are guaranteed at least one copy of each hero once you unlock them - that is, once you unlock Ninja, your next hero will be a Ninja. A mixed team works decently well, and it gives you more options. Buy strong weapons in the shop(see weapons section below). I also recommend buying certain mods( also see below). To avoid fatigue, either battle as second time or use the roulette to earn food. Money is reasonably plenty, so I recommend the latter. Focus on training a few heroes - a few solid suggestions are engineer, juggernaut, merc, and- elite. See below for class/abilities guide
Late game
You'll be able to cheese the scenarios pretty handily. The only problem will be the gun game scenarios that depend on hp(level). This is one of the few stages in which Rocky(assuming you trained him) will excel, so it may be worth sticking him in for this. The game will actually get easier as you advance, simply because the enemies cap out in difficulty and you continue to get stronger.
Gun Game Primer
90+% of the gun games in the campaign are very similar, beginning with a crossbow. You'll want to gain an early lead, since weapons only get better. Part of this requires excellent crossbow skills - the crossbow has huge damage, is your opening weapon, and has atrocious reload. You want to make sure that you hit, preferably on the same target that a teammate has shot for an instant kill. From there, things will tend to get easier, as you advance up the weapons tree. After chessing through rockets, you'll have to work with the thumper. Aim to deliver both grenades to the same target in rapid succession, and your mission will be complete. Near the end, you'll have to use elementals(freeze/acid hound). Above all, avoid killing yourself. To do so, aim a little higher to avoid ground-splashing yourself. The last three kills are trivial, as they utilize excellent experimentals, so once you're there, it's almost impossible to catch up.
Devs a la muerte
This is probably the only difficult challenge in the game. On easy, it's not terrible, but on normal/hard, things start heating up. As an overview, you have 4 kills each of normal, defensive stance, stealth, heal, and hax. The last 5 kills combine everything, and they gain double weapons for the last two. While the first four phases are quite easy except for possibly stealth, hax will begin to negatively impact your k/d ratio. At that point, you just want to finish the game using the lead you built up over kills 1-16. The hp of the devs thankfully remains constant, with Justin being somewhat weaker than Mike. It greatly helps if your weapon can one-shot at least Justin, and the scenario becomes a cakewalk if you can one-shot both. Such weapons include the Tank Buster, Fortune's 500 and Rehab. You may have to upgrade these weapons. Avoid closing in to close range, and shoot from afar. Alternatively, wait until they pass underneath a platform before unloading ammo into the back of their head from above. The AI has a significant weakness to this kind of attack. I also recommend life support module - while mostly ineffective, every inch helps.
L33t Weapons
*Intervention (Gold=rehab): An all=around sniper rifle with great RoF compared to the L115(inverted from SFH2), but slightly lower damage.
*Railgun(Fortune's 500): A high dps sniper rifle, similar to the intervention, but for different classes. Overall, slightly higher Rof and lower damage than Intervention, which means it benefits from a damage upgrade to ensure OHKO
*Panzer(Tank Buster): A homing rocket launcher. What's not to like. Even though drum mag no longer gives infinite ammo, 7 rapid fire rockets is still pretty absurd.
*AK12 (Iron Curtain): Sprays bullets accurately for high damage. Just OP, even non-golden. Only weakness is small mag size, which can be fixed by extended mags. Unfortunately, AI's only use the Iron Curtain in small bursts. Even then, it's absurdly OP, and earns my vote for MVP weapon.
*Ion Cannon(Paralyzer): The MVP of noob guns. I've carried matches against lvl 30s as a lvl 12 with a paralyzer. The paralyzer gains significant damage over the ion cannon, and upgrades further help. Although it has somewhat limited range, it's more than enough for much, and you don't have to worry about self-injury like an elemental. The gun 2-3HKOs every enemy, and fires at an absurd speed. I suspect the DPS rating is misleading/wrong. While it somewhat worsens your personal K/D ratio, it racks up so many kills that the overall team K/D ratio improves, partly because they're too busy re-spawning. Unfortunately, it somewhat requires player control to reach absolute OP status.
*R870(Defriender): The R870 is a solid shotgun, but has meh damage. But, the defriender gives it huge range, making it tactically viable and an all-around solid weapon.
*DB12(Boomstick): Basically the quintessential close-range shotty. Unloads double shots, making hash out of any target. The Boomstick takes this one step further. Main weakness is crappy range.
*Commando(Bennett's Doom): The commando looks spectacular, but pales in comparison to drummag tank buster, even post nerf. Bennett's Doom restores a lot of the power due to its instant flight projectiles. Unfortunately, guaranteeing an OHKO basically requires you to empty your magazine of all 4 shots, so you end up quite vulnerable.
Strong, but not game-breaking weapons
*SMAWG(Dragon's breath): A solid rocket launcher that does about as much as tank buster, but non-homing. Still benefits strongly from drum mag.
*SAW: Sprays impressive bullets, more so than the vulcan, but still somewhat weak DPS.
*DSR-1: Powerful DPS, but funny trajectories. Difficult to use unless you are an AI, which prevents it from being totally OP.
*Pulse Rifle: Good DPS, but not great. Freeze is too slow/infrequent to use generally. Overall, solid, but not game-breaking.
*MTS 255: Solid shotgun, but not game-breaking due to manual fire and lack of OHKO alpha strike.
*Most other sniper rifles fall into the category - decent DPS, but not OP. due to lack of OHKO alpha strike
*A fair number of duals enter here. To be fair, I'm not a big fan of duals in general.
*Most other rifles are solid, but not OP. The Fal OSW/Peacekeeper is good, but requires a lot of clicking, which makes it AI-suited.
Garbage Bin
Basically everything else.
Perks, weapon mods, and others
*Drum mag: Amazing for rocket launchers, and anything else you think would benefit from no reloads.
*Extended mags: The winner for most machine guns due to increased time between reloads
*Spare mags: Generally inferior to extended mag, but still a solid option for any ammo-hungry characters.
*Burst fire: Interesting, but I personally avoid using.
*The following describes perks, which are unlocked at levels 5, 10, and 15. You are given a choice between two perks at these levels, which you can freely swap.
*Most red/offensive powers just suck. They make too small of a difference to matter. 10% is unlikely to win or lose a fight.
*Yellow powers are mostly weak, but better than offensive. Cash/exp is useful at times, as is no-fatigue, but it doesn't really matter. Resourceful(bigger health/ammo pickups) is handy, as are the killstreak abilities(exception: muscle memory sucks, as you must earn your streak for it to be saved). Quick respawn is funny, but can end poorly. Stealth can be handy, but only for certain characters that appreciate melee distance.
*There are 3 blue powers that are game-defining. The more a character has, the better they are. The first is healthy(always regenerating). It's not that strong on its own, but can be combo'd for extreme awesome. The second is adrenaline(survives fatal attacks w/h 1 hp), a useful skill for tough matchups with heavy OHKOs. The third is Repair Bots(heal 3x faster).
*All of the red, yellow, and blue abilities can be found the casino machine, or as mods. Nanomachines are great to purchase, as are life support kits(which yields 3x heal and adrenaline). If a character has to choose between healthy and repair bots, I typically choose repair bots.
Flaws, Assets, and killstreaks
These really don't make a difference in general. Energy Ammo and the Ninja stealth are the only ones that change how the game is played. Energy ammo regen is too slow for heavy duty killing, so you'll eventually run out of ammo, but that's probably not concerning if you just racked up a 30 kill streak. Ninja stealth is something that I rarely use. The medics' rapid re-spawn 'asset' is actually a problem, as it often glitches respawns and resets them. It's the only asset that I recommend firing someone for.
The most debilitating flaws are no regen(just fire the loser), shortened kill streaks, and squanderer(low ammo pickup). Everything else is not terrible, and the perks unlocked at 5,10, and 15 matter more(except no-regen).
Every class also has two killstreaks - most are similar, so I'll only highlight the ones where one is significantly better than the other.
*Rocket turret's range beats shotgun turret handily for engineers.
*Deadly shurikens is solid, but smoke bomb opens many more options for a ninja.
*Ice ray's global freeze makes it stronger than death ray for elites.