I'll be honest here. I don't play the game very often, and I'd love to use a cheat editor to level up my perks automagically. But I don't feel like getting banned, so I'm content to just grind up for a bit. What would you suggest as the best ways to level up my perks? I'm looking for info on all perks, but any way to hit max speed on demolition would be appreciated most.
Hard to really know. For Support Specialist I know that if you unweld a door and then weld it again it still counts, so you could theoretically just sit there welding/unwelding a door all day assuming monsters don't come and eat you.
Play on those Doom2 Final servers. It's a small map, and you can level up faster there. I'm trying to hit level 4 demolitions myself, and that map makes it easy to set off pipes, which contributes over 1k points per bomb. If I survive all 10 waves, that's over 100k points of damage.
Sharpshooter - do not use akimbo pistols. Yes, you get higher damage output, but damage is not what you are leveling. Always go for headshots. Despite the slow reload, the Crossbow is THE weapon of choice for a sharpshooter against Scrakes, Sirens, Husks, Fleshpounds, and the Patriarch.
Commando - this one's hard, since the only kills that count are the Stalkers. On lower difficulties, I recommend toting around a Bullpup or AK while using any other perk, so that you can switch to that weapon to kill those Stalkers. Remember, you can level up most any perk while playing another perk.
Support - Weld AND un-weld doors. You get points both ways. When playing on a team, be sure to only weld doors that are helpful to the team. When solo, whittle the wave down to one clot, and lure it thru a doorway, weld the door (maybe even tape down the mouse button and walk away for awhile).
For shotgun damage, wait until the enemy is close to do the most damage possible. Also, akimbo 9mms and HandCannons add damage points to this perk, so maybe going sharpshooter for a damage boost, and going akimbo on Body-shots instead of headshots to help level up the Support perk.
Medic - this one's hard, because you can only level it up on Multiplayer by healing other people, so heal your team mates often. Equip the medi-gun and use the secondary fire to launch a healing dart at team mates from longer ranges, and while that's recharging, equip your medical syringe, and run in for close-range healing. if you have a friend, maybe whittle down the wave to just one clot, and have your friend take damage while you go about healing them. Power-levelling for the win!
Firebug - get the Flamethrower, and MAC-10 as soon as possible. Use the flamer against clots, gorefasts, crawlers (try to leave the Stalkers for the commandos, but the flamer works great on them, too). Use the MAC-10 against Bloats, Husks, Scrakes, and Sirens. Let other team members handle Fleshpounds. At lower difficulties, the Flamer is surprisingly useful against the Patriarch.
Berkzerker - Equip melee weapon of choice, and do your best to avoid taking hits with the speed boost and tougher armor. Might be helpful to have a friend pop the head off the enemy first, and then go after their shambling body, since you do more damage once their head is off. Bloat acid can be the bane of your existence, so be careful of those fatties. Chainsaw slows you down a LOT, losing your speed advantage. Machete and Axe are good to find around a map, and for the first few waves. Recommend upgrade to Katana ASAP. Give extra money to team mates to help them buy their more expensive weapons.
Demo - Blow. Up. Everything. Easier to do on solo since you'd be blinding your team mates otherwise. M79 is a good starter weapon, laying pipe bomb traps is yet another good way to do it (see above comment about 1,000 pts of damage per bomb). M32 is useful for handling larger groups.
I also found that at lower difficulties, the reload-speed bonus for the Commando helped get the lead out when firing the M79 and M32 launchers, so while the damage wasn't there, I could keep in the fight. At higher difficulties, this is definitely NOT recommended.
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If you play on friendly-fire enabled servers, it's much easier to level up the Medic perk if your teammates let you smack them with a katana between enemies.