A Few General Comments about The Classes
Every offense uses scouts. They are easily the fastest class in MegaTF, and can outrun or outmanuver any other class. The scouts jetpack gives him the ability to increase his speed even further and fly upwards and over obsticles.
The scout also has concussion and flash grenades. Concussion grenades will cause the screen of anyone who is hit by them to swirl, making it difficult to aim and walk. Flash grenades will make anyone hit by them unable to see. Their entire screen will go white for a few seconds. Plenty of time for a good scout to slip by.
What the scout has in speed, he lacks in strength. You will need to use your jetpack to avoid or get past enemies, and your flash and concussion grenades to incapacitate your opponents. Even great scouts die a lot. Don't let that get to you. Every time you manage to move the enemy flag further out of the enemy fort is a successful attack.
Key Commands for a Scout:
jetjump - by default, this is assigned to the spacebar
Good Against: Snipers, Heavy Weapons Guys.
Weak Against: Soldiers, Pyros, Engineers.
The one-shot-one-kill specialist. Snipers can help a defense survive against a talented offense, helping to break the pressure and slow the enemy's assault.
This is another hazardous occupation. While scouts die frequently, snipers may kill each other even more often. You need to prioritize your targets to survive as a sniper. Generally, I recommend focusing on killing enemy snipers first, then enemies on the ground. Ignoring an enemy sniper for a few seconds is all the time he needs to finish you off.
A few important things about sniping:
Learn to hide, and teach yourself to shoot on the run.
Use airstrikes. They MUST be set outside, and you only get one per life. Even so, an airstrike is a powerful tool. Hold down the fire button for a few seconds, and then hit the airstrike key (by default, this is the q key). That will create an airstrike marker wherever your gun was aimed. About 30 seconds later, bombers will obliterate the ground near that marker, killing everyone in the area.
Key Commands for a Sniper:
zoom in/zoom out - by default, this is assigned to the spacebar
airstrike - by default, this is assigned to the q key
Good Against: All classes except scouts, at a distance.
Weak Against: Scouts, spies.
Some would call the soldier the most versitile and widely used class in MegaTF. Most defenses use numerous soldiers, and most of the best players in the game are at least fairly good at this class.
Good soldiers are always in demand. The soldier uses the rocket launcher, and since he can carry 50 rockets, he is rarely low on ammunition. By using his spike traps and proxy grenade wisely, (as well as his own durability and destructive power) soldiers can defend against light classes very well.
A soldier can kill any class, but has more trouble with the more durable heavier classes like Demomen and Heavy Weapons Guys than he does with the less armored classes.
Key Commands for a Soldier:
Reload - by default, this is assigned to the q key
Drop1 (spike traps) - by default, this is assigned to the z key
Drop3 (proximity grenade) - by default, this is assigned to the c key
Good Against: Most light classes.
Weak Against: Demomen, Heavy Weapons Guys.
Armor 100 Blast Armor - Takes less damage from rockets and explosions, but is weak against bullets.
The demoman is a walking explosion waiting to happen. His explosion resistant armor makes him very good against soldiers, and a favorite class for offense. Unfortunately, his armor is weak against projectile weapons, like those carried by the mdeic, sniper, and heavy weapons guy.
The demoman can also place pipebomb traps which he can detonate at the touch of a button, killing anyone standing nearby. Good piping makes a demoman a very capable defender. A good demoman can make it very hard on an offense that has to pass through a narrow area to get to your flag.
Finally, a demoman can set detpacks. When the timer on a detpack reaches zero, it will kill every enemy within its line of sight instantly.
Key Commands for a Demoman:
Reload - by default, this is assigned to the q key
Detpipe - by default, this is assigned to the spacebar
Detpacks - by default, these are assigned to the ctrl and alt keys
Good Against: Soldiers
Weak Against: Medics, Heavy Wapons Guys
Health 90 - Heath Recovers slowly whenever injured
The medic is a great support class. Used primarily for defense, he can make it significantly more difficult for a group of attackers. By hitting teammates with your axe, you can restore their health. You can also heal concussions, flash grenade blindness, spike trap or leg shot damage, or hallucinations from spy gas. All of these can really help a defense, who (at some point) will be suffering from one or more of these injuries. In addition, you can fill an engineers dispenses with health, allowing people a long way from the resupply rooms to recover from damage.
A medic can do more than heal others though. He can hold his own in battle against most other classes. By hitting enemies with your axe, they'll slowly begin to die from infection. Your enemies will eventually die from even a single hit from your axe, unless they are healed by an enemy medic or kill themselves. The medic also has one of the best guns in the game, the super nailgun, making him a dangerous adversary.
What the medic has in firepower and speed, he lacks in durability. To be effective as a medic, you need to dodge well and use your concussion grenades to keep your enemies off balance.
Key Commands for a Medic:
Drop1 - by default, this is assigned to the z key
Use your axe to heal allies or infect enemies - by default, switching between your axe and supernailgun is bound to the e key
Good Against: Demomen, Pyros, Heavy Weapons Guys
Weak Against: Soldiers
Heavy Weapons Guy
A walking tank, with firepower to match. The fact that he is slow is about the only negative about the heavy weapons guy. Good for defensive and offensive use.
The Heavy Weapons Guy is deadly. Most other classes can hit a Heavy Weapons Guy with everything they have, and they'll fail to kill him. The 20mm cannon fires 10 shells at a time and can rip throuh your opponents. Your assault cannon fires a constant stream of ammunition at the enemy. While this may seem to make a Heavy Weapons Guy unstoppable, be careful. Once you're out of ammunition, you're easy prey.
Key Commands for a Heavy Weapons Guy:
Drop1 (Spike Traps) - by default, this is assigned to the z key
Switch between the Assault Cannon and the 20mm Cannon - by default, this is assigned to the e key.
Good Against: Demomen, Soldiers
Weak Against: Pyros, Medics
Armor 150 Flame Resistant Armor
Speed: Very Fast
Speed, and tremendous damage potential. The pyro is a fairly versitile class, able to do many things well. Armed with a flamethrower and a naplam rocket launcher, the pyro can set enemies on fire and burn the opposition down.
Primarily used defensively, a pyro can make it difficult for light classes to attack any small area. His speed gives him the ability to pounce on the slower, heavy classes and burn them to death.
Key Commands for a Pyro:
Drop1 (Lava Trap) - by default, this is assigned to the z key
Good Against: Heavy Weapons Guys, Scouts
Weak Against: Soldiers, Demomen, Engineers
Sooner or later, someone on the enemy team will get the idea of building a sentry gun to protect their base and flag. While your team can use a lot of heavy classes to attack and eventually overpower the enemy's defenses, it may be a lot easier to sneak in as a spy and blow that gun apart with grenades.
Spies are a very valuable asset to an offense. First they can disguise themselves, appearing to be a member of the enemy team. Your enemies may let you just walk right past them, if you're clever enough to disguise yourself well.
Another bonus, when you are disguised, enemy sentry guns will not fire on you. Of course, you can't shoot at the sentries and stay diguised, but you can toss grenades at them.
The spy is an expert with the knife, and can kill most light to medium classes instantly when stabbing from behind. A spy knife attack is much more powerful than any other class.
Spies also get a grappling hook to scale walls and sneak into hard to reach areas. The main weapon of a spy is the traquilizer gun, which slows an enemy to almost a stop. This makes them easy to stab to death silently.
Spies can also fake their own death, and remain hidden as a corpse. When the enemy defender leaves the area, the spy can get back up and continue to attack.
Finally, each spy is given an ammo trap. It looks just like every other backpack full of ammunition, except when an enemy touches your ammo trap, all of their ammunition disappears. Once this happens, even the most dangerous classes are at your mercy.
The one weakness of a spy is just that: he is very weak. One grenade will kill him. It takes very little firepower to kill a spy, once he's been uncovered.
Also - avoid enemy scouts when disguised - they will uncover your disguise.
Key Commands for a Spy:
Drop1 (Ammo Trap) - by default, this is assigned to the z key
Disguise (Disguise as the other team to sneak past guards and sentry guns) - by default, this is assigned to the spacebar
Feign (to fake death) - by default, this is assigned to the t key
Good Against: Snipers, Engineers, Sentry Guns
Weak Against: Soldiers, Demomen, Heavy Weapon Guys, Scouts
Each engineer can build a sentry gun and an ammunition dispenser. Both are crucial to each team's defense. While a team can get by without a sentry gun, building a sentry gun near you flag and protecting it from spies will significantly increase your team's chance of winning the game.
Both also take cells to build. A sentry gun takes 130 cells to build, and 130 more for each upgrade. An ammuninition dispenser takes over 100 cells to build.
Once a sentry guns is built, it can then be upgraded twice. A level three sentry gun can kill any class almost instantly. If fires both shells and rockets, and only disguised spies can get within it's line of sight without being fired on.
Light classes are typically slaughtered by a sentry gun. Heavier classes and spies will attempt to use grenades to kill your sentry gun, but the rest of your defense will have an easier time stopping the slower, heavier classes knowing that the lighter classes will be devoured by your sentry.
Engineers also get a magnetic mine. When an enemy steps on this, they will be trapped in place for 15 seconds. Use the opportunity to throw your grenades at them from a safe distance, or around a corner.
A bit of advice: watch out for spies. Shoot anyone coming into your flag area. If they take damage, jump higher than any other class, or cry out in pain when you shoot them, they are a spy. Chase them down and kill them before they get your sentry gun. Spies are the bane of your existance as an engineer.
Key Commands for an Engineer:
Build (To create a sentry gun or dispenser) - by default, this is assigned to the spacebar
Drop1 (Magnetic Mine) - by default, this is assigned to the z key
Drop3 (Laserdrone) - by default, this is assigned to the c key
Good Against: Scouts, Pyros
Weak Against: Spies