Goon Survival Guide
This is a list of a bunch of really common tidbits of advice that pop up in the thread on a regular basis. If you follow all of it, you've got good odds of making it past Dreadfell.
Wild Infusions that remove Physical effects are incredibly good. Being stunned or frozen will account for a huge chunk of your deaths if you don't have one, or if you fight when it's on cooldown. Your starter Physical Infusion can easily go unreplaced for an entire winning run, and often should.
Always have an escape option. Movement Infusions, Teleport Runes, and Controlled Phase Door Runes (or talents/generics that grant you equivalent effects) can and will save you when you inevitably wind up in a fight you can't handle. Warp out or Run Away, heal up, give your cooldowns time to reset, then go back in for another round.
Replace your starting Shield Rune/Regen Infusion with better ones ASAP. Scour the various towns' Infusion and Rune shops, the starter Shields and Regens are very weak.
Jesus christ, put at least one point per level into con. HP is good, and HP+thick skin is even better. You really don't need to boost your mag/str/dex/cun over what you need to level skills before going to the east.
Getting a high light or infravision radius is invaluable in unlit dungeons, it sucks horribly to bumble around with a radius 2 light while a mage nukes you down from the darkness.
Stun/Freeze immunity is extremely valuable, but not necessarily worth sacrificing gear in other places over. If you've got two roughly equivalent pieces, go for the one with stun/freeze immunity. Always max abilities that give you stun/freeze immunity, they're essentially never a bad choice.
Stealth/Invis detection is often very helpful, as sneaky types tend to drop a lot of spike damage and hurt a lot, and can ruin your day if they get the drop on you.
Dig is GREAT. Abuse dig to set up fights favorable for you. For melee characters, this means narrow, winding tunnels that force enemies to step into melee range before they have Line of Sight on you so you can shred mages without spending multiple very painful turns closing the gap on them. For ranged characters, this means opening up a way to shoot at enemies from afar, and leaving yourself room to kite them. Fighting on advantageous terrain can turn fights from guaranteed death to easy loot. The Kor'Pul shade is a notable example of this, if you charge through the dark corridors at him he'll probably kill you unless you're really overleveled, but if you dig through the wall next to him, you'll probably murder him very easily.
If you have the chance to get it from an Escort quest, Celestial/Light is truly excellent. It comes with a good heal, a good shield, and Providence, which is arguably the best defensive ability in the game, as it will cleanse a debuff from you every round for several rounds, making you somewhere between highly resistant and completely immune to any and all CC, unless enemies are laying down CC really, really heavily. Technique/Conditioning is a good tree for the same reasons - gives you some really excellent CC resistance and makes DoTs (which are murderously lethal in ToME) hurt a lot less. Stone Alchemy is another solid Escort tree, it can make you very, very rich, which can give you access to some ridiculous strong (and expensive) gear.
Side with the Assassin Lord once for the Poisons Tree, then never again. Saving that Merchant is what gives you access to the ridiculously strong+expensive gear previously mentioned.
Anti-Magic is probably worth getting if you have access to it (ie are not a dirty magic user - if you're magic you won't even be able to see the Anti-magic town). You'll eat some gear restrictions in exchange for two very good generic trees. Particularly worth getting on classes that use Equilibrium, as the Fungus tree will give you nigh-infinite Equilibrium.
Related to AM, don't try to do the AM trial at level 10, when it first unlocks. Unless you're really strong or really know what you're doing, you'll probably die. Wait until 15-ish.
More AM chat, check your gear (in particular your weapon) to make sure none of it is Arcane. Stepping into the AM trial and having the game strip off all of your gear is a very humiliating way to die.
Urkis is a pain in the ass, but if you can clean off the Hurricane debuff (it's Magical) he hurts a lot less, and if you go all out offense on him, he tends to crumple quickly - he's a glass cannon
