Strategy:Melee Types

General

Melee weapons are not very useful in general games because they are inaccurate without any levels in Brute and do not deal enough damage to warrant their inconvenient range unless you are berserk. And, of course, if you're berserk then you might as well just shoot things - you'll get the massive bonus that berserk gives to your resistances either way.

Attempting to conquer the game is one situation where a shooting strategy with melee as a secondary priority really works. Work towards a melee master trait (get the non-brute requirements first, though) and shoot things until they die as you normally would. Once you have your melee master trait, you can easily clear out the Unholy Cathedral on floor 17 (in fact, you could probably fight the Cyberdemon with your chainsaw too) and claim your artifact melee weapon. From there the game should be reasonably simple; you have an extremely powerful murderstick and the traits to use it - go nuts!

Angel of Berserk/Melee-based Characters

Unless attempting a Gargulec Medal run, don't try to kill everything. Sergeants and, on higher difficulty levels, demons will be difficult to deal with.

Sergeants, if they're getting in the way, can be dealt with by giftdropping but demons represent a source of unavoidable damage - they're faster and stronger than you, so run away before they get close! Also, hell's arena will murder you good - stay away even if everything's going great, it won't be worth it.

Other enemies will be a nuisance sometimes, but their attacks are much easier to avoid than the sergeants, who never miss, and the demons who are better at melee than you are right now. Use running mode and sidestep their projectiles as you approach to reduce the accuracy of other enemies, such as former captains and imps, to almost nothing.

As long as you have the Berserker trait by the time you're finishing up in The Chained Court then everything should be fine for the midgame. Once you have that trait and the chainsaw, you should still avoid fights with powerful enemies unless you're berserk. However, the trait will help you with that:

Berserker will make you berserk (which is basically super speed + extreme resistance to damage + deathtouch now that you have a chainsaw) after roughly 4 melee attacks in quick succession, or if you take a large percentage of your max HP in damage. Attacking four times means that you're probably taking damage from fighting, so Berserker only really works when you're willing to spend health on it. If a fight looks too dangerous to run in and get a berserk chain going, walk around the edges of the level and look for smaller fights or big powerups.

Once you defeat the cyberdemon and then clear the Unholy Cathedral - which is simpler than it sounds, you're rather good at 1v1 by this point - you will be given an artifact melee weapon, almost certainly the Longinus Spear. It deals enough damage to instantly kill anything, so at this point your only problem is getting close to your victims. Or, because you're certainly powerful enough to tear the final boss in half, you can just dive straight down to level 24 and do that.

Melee Marine - Vampyre

Vampyre is a rather straightforward melee trait - it gives you HP back when you kill things, so the downside of Berserker (that it generally costs HP to activate) suddenly gets a lot easier to deal with in early levels.

Remember that you can farm pain elementals (or arch-vile respawns, for the daring marine) for decent HP gain if you do it right.

Melee Scout - Blademaster

Blademaster gives you a free turn every time you kill something, so you can be more reckless when approaching groups of enemies. You're quite fast with Hellrunner 2 and the scout's natural speed, so a bunch of enemies won't get too many shots on you as you quickly run in and instantly destroy them one by one. If there's a lot of enemies, you'll probably even get Berserker to activate, at which point the fight becomes even easier.

Melee Technician - Malicious Blades

Malicious Blades gives you berserk-like resistance to all damage types except for acid and plasma as long as you have a knife (or other blade, chainsword and Azrael's Scythe for example) in your prepared weapon slot.

This can be extremely useful for melee characters who normally can't fight ouside of berserking, although you may have to watch out for arachnotrons and former commandos, because their attacks will go through your resistance and are fairly accurate even to a character with dodgemaster. It is also useful for ranged characters in some cases, because you don't need to actually use the knife to get the bonus, only hold it.