Markov is the tier 1 assault, capable of dealing massive amounts of damage using his lightning gun and arc mines. His secondary is a low-recoil, fast-firing assault rifle that is still pretty decent from a medium-long range. Markov is a strong assault, if not the strongest. He's fairly easy to play and great to have on any team.
How to play as Markov
When engaging the monster, use the lightning gun first to draw his attention and deal some solid damage. Once it's out, you have probably attracted the monsters attention and need to use your shield to prevent a severe beat-down. During this time you can safely deploy arc mines around the monster, taking huge chunks of the monsters health every time he gets too close to one.
By this time, it's probably best to drop back and deal a little less damage from a safer distance while you heal up and give your shield time to recharge. Toss down a few arc mines (the dome's probably getting weak at this point) and begin your assault again.
If the monster starts to get too far out of range, you can do a little more damage with the assault rifle by putting a clip into his backside. Rinse and repeat.
Parnell is pretty fun to play, but is definitely the risk-taker of the assault class. Using his super-soldier ability, Parnell is capable of doing some really impressive damage - at the cost of his own health. Paired with Cabot's and his damage amplifier, Parnell's rocket launcher will shatter the monster like glass.
Like Markov, once Parnell's shield is down it's a good idea to ease back. By the time your team needs you, your shield will be ready to go again.
Although he's a bit weak, he's not completely useless. To effectively use Parnell, you must be cautious when using super-soldier and be ready to bring on the pain once you do. If Cabot's on your team, give him a heads up before you go nuclear.
Val is the tier 1 medic. Although she's a little weak in both heals and damage, she provides 2 great advantages for your team: armor-piercing sniper rounds (allowing your team to really hit the monster where it hurts) and tranquilizer darts (which temporarily slow the creature a great deal and provides a green glow to track the creature (even when behind objects).
How to play Val:
Val works best from a distance. It's best to be lurking in the shadows, high above on a cliff - anywhere but close to the monster, really. Her offense and defense are almost non-existent, but she's fairly quick. Her healing gun's "hey look at me" glowing trail of green is just monster baiting.
She's effective from a distance, so she can maintain a safe distance while still being useful. It's probably a good idea to stick with the assault or support. Lone medics make for tasty monster treats.
Lazarus has a very unique advantage over his colleagues: he can bring the dead back to life.
Equipped with a silenced sniper rifle and personal cloaking device, he is really one sneaky son of a bitch. Monsters hate him, teammates love him (except when he doesn't heal) - hell, he can even revive dead animals and ensure the monster cannot obtain elite creature buffs without putting in the work for himself.
How to play as Lazarus
Lazarus requires a good degree of stealth. Unlike the other medics at release - Val and Caira - Lazarus does not heal teammates directly (except through the class ability - healing burst).
If you get too close to the monster, he will try to take you out - there's nothing more infuriating than killing a hunter just to turn around and see him brought right back into the fight. Lazarus isn't a fighter, he's a survivor. Sometimes that means saving his own ass while the rest of you are getting pummeled, but he'll come back and revive those that didn't get eaten.
The sassy, smart mouthed, always helpful Caira has an advanced grenade launcher that fires both napalm and healing grenades. She also comes equipped with by an adrenal-stimulating speed perk for teammates lucky enough to within range of this medics with the funky pharmas.
How to play as Ciara
Caira isn't afraid to fight - but her teammates prefer her to keep them alive with her (best health restorer in game) healing grenades.
Caira's speed boost provides a huge advantage when pursuing the monster, letting her teammates cover twice the ground during the heart-pounding adrenal boost.
It's best to stay close to teammates whenever possible - if you have their back, and they'll have yours.
Maggie is a 2-for-1 special. Her pet trapjaw, Daisy, will attempt to track down the monster by sniffing him out. Daisy will also attempt to revive fallen teammates, and just kind of chills in the back during combat. It's best not to depend on Daisy too much to track the creature - she'll always be a step behind if the creature is moving fast, but she really comes through for the team if the monster is attempting to hide.
How to play as Maggie
If you're really lost, Daisy can pick up a cold trail (you have to let her lead or she'll just blindly follow you). Maggie can lay down up to 5 harpoon traps, putting the monster in a very tight spot for a few seconds. This provides a huge advantage for your team, and you should use it often before during and after the arena.
Maggie's primary weapon doesn't do much damage, but it can free a trapped teammate, take down the smaller creatures with ease, and provide additional firepower while having to retreat to a safe distance.
Griffin is a rambunctious Aussie that's lucky to have on your side. Griffin can deploy up to 5 sound spikes to track the creatures movement. These spikes cover up to 100 meters - nearly half the map if placed properly.
Griffin is also equipped with a mobile harpoon gun. It takes a steady hand (if you miss, you'll have to wait a few seconds for it to reload), but it does wonders for keeping the monster at arm's length a little while longer.
Griffin's primary weapon is the Gauss SMG, capable of delivering decent enough firepower to be felt and dispose of weaker threats.
How to play as Griffin
Griffin can get in close and retreat pretty easily. Harpooning often will direct the monsters focus to you, so it's best to get out of the way and fire from a respectable distance once this happens. Aside from some solid dome action, Griffin can just sit back and relax until the monster inevitably walks into a sound spike and gives the team a place to look.
You can keep an eye on your sound spikes by pulling up the map - both monsters and Shear's creatures can trample one down at any time.
Abe is the master of tracking and trapping, cleverly booby-trapping his enemies food supply with his trusty tracking dart pistol. Abe is also equipped with stasis grenades, entangling his target with intense energy to restrict movement.
The custom shotgun doesn't do a lot of damage, but your accuracy and range will improve if you use a slower rate of fire.
How to play as Abe
Like the other trappers, it's better to track him, trap him, and stay out of the way. If you aren't fighting or setting up the arena, you should be shooting wildlife with tracking darts to increase the chances the monster eats one.
During the fight, your best weapon is stasis grenades. Landing multiple grenades will greatly improve your teams ability to deal out damage and heal up while staying out of harm. Make sure to shoot the monster with the tracker on his way to Tail Tuck Mountain.
Hank is a rough character, but he's here to keep his teammates safe and kick some monster ass.
His primary benefit over other supports is the shield gun, which will temporarily shield any damage being dealt to the targeted ally. This draws a good deal of hatred from the monster, but it also saves lives.
His rocket barrage is a bit lacking, though does very nice damage if it fully lands. To reach maximum damage, the monster must be trapped in the same spot for about 5 seconds.
His primary weapon, the laser cutter, is one of the best in support. It deals out a respectable amount of damage, though it's a bit heavy/unwieldy and has a somewhat small magazine.
How to play as Hank:
You are the team's guardian angel, the one that saves them from being consumed in fire or abducted by a viscous wraith out of nowhere. You have to be fast. You have to be sneaky. You can't be afraid to get in close to deliver some damage and run when the time is right (if it comes to that).
Bucket is a sophisticated piece of machinery equipped with a laser-guided rocket launcher, can use his head as a UAV to find and track the monster, and place up to 5 sentry robots for protection and extra damage. Although somewhat tricky to control, Bucket is in a class of his own when it comes to supporting his teammates.
How to play Bucket
If there are no visible leads at the start of the map, go ahead and find high ground to send out a drone. It's always a good idea to place a couple of sentries in case you're left alone (almost always) - more if the monster is higher than stage 2.
Stealth is a key perk of the support class, and Bucket can use it to gain a tactical advantage. While cloaked, it's a good time to reset your sentries if needed and give your medic a little breathing room to heal and revive before retreating to a safe distance.
The rocket launcher is quite useful, though requires a bit of planning to land the rockets in quick succession.
Cabot so troll. Equipped with this super cool rail gun, you can shoot thru walls (at 50% damage). This is great for confusing the monster and keeping him off the power relay long enough for your teammates to drop back into the fight.
He also has a unique ability to "dust" an area with radioactive isotopes - highlighting the monster for a fairly long time (20 seconds?). This even works against the Wraith, and will highlight him again once his decoy is expired.
Finally, and his most important role, is the damage amplifier. A well timed amp will really turn the tides of battle, chewing through the monsters armor and core at an alarming rate. Watch Goliath yip, Kraken fly off, and Wraith slither off into the distance as they enter panic mode and run for their lives. Be sure to coordinate with your assault and other teammates so you they're ready to unleash when the amplifier goes hot.
How to play Cabot
Cabot is all about choices. Knowing what to do and when to do are crucial to being effective with him. The rail gun does great damage, but you have to re-chamber after each round. Aim is critical. The damage amplifier is the most useful damage tool in the support arsenal, though it doesn't directly damage the creature itself.
You will be targeted, but you can target him too. The only time you'll need to get in close is when you're amping, and it has a fairly good range. Stealth and get back if it gets too hot - your team can respawn while you trololool.