Unlockable characters

Here's a quick little guide on how to unlock extra characters to play in Marvel Ultimate Alliance.

Dr. Strange

Dr. Strange will be unlocked in the Valley of Spirits. Help him find his lost artifact, and he'll join the roster. Here's where you'll find it:

Blade

Blade will be unlocked if you win the claw challenge in the Murderworld level, it's hard to miss and simple to win.

Ghostrider

You'll find Ghostrider in Mephisto's Realm normally as you play.
You will have to sacrifice one of your characters to unlock him, but no worries, you'll get him/her back upon completing the level.

Daredevil

Within the levels there are little action figures, hidden in specific locations. You'll have to collect 5 daredevil action figures to unlock him. When you do, the remaining figures will turn into XP bonuses.

Black Panther

Pretty much the same deal, collect 5 action figures, and the character will be unlocked.

Nick Fury

Unfortunately, the hard difficulty is locked when you start the game. It will be unlocked along with Nick Fury as a playable character when you will finish the game on easy/normal mode.

Silver Surfer

This one is the hardest to get. To unlock him, you will have to find every simulation disk hidden within the levels, and beat every sim mission with at least the bronze medal.

Extras

Since this guide is fairly brief, here's some extra info:

DLC characters dialogue achievements:

Mutant Love (Cyclops has spoken with Jean)
Get Cyclops as your party member before travelling to the Murderworld (there will be no checkpoints, and the portal will be shut, so keep your boi safe), special dialogue will start when you'll save Jean from an arcade machine.

Fleeting Allies (Magneto has spoken to Xavier)
Get Magneto as your party member to Mephistos Realm. The dialogue wont take long to start.

Wrong Claws (Sabretooth has been mistaken for Wolverine)
This one's a bit far fetched... Get Sabertooth as your party member to the Shi'ar level. You'll get the special dialogue with Gladiator and Deathbird.

Doppelgänger (Doom has spoken with himself)
Get Dr. Doom as your party member to the final level. You'll get the dialogue upon encountering the real (?) Dr. Doom.

Unlockable costumes:

For the regular characters, you will get the first additional costume by killing 30 enemies, the second for killing 150 enemies, and the third for completing the respective comic book simulation level.

For Colossus you will just have to get 30 and 150 kills, as his third additional costume is unlocked from the start.
For Moonknight you will just have to get 30 and 150 kills, as he doesnt come with third additional costume.
For the DLC characters you will have to get 250 kills to unlock all of their costumes.

Conclusion:
Once again, the guide is pretty brief, but I hope it helped somebody, as there were none on Steam so far. Best of luck to y'all.

[noble.]

Is there a way to do mods on here?

[Vanom]

I've missed only Silver Surfer then...

[Uncle Remus]

Yes.

[Mad-Rujia]

So the dlc characters come witht he game?

[blackmanta86]

Good shit bro, glad some guides are finnally up here on STeam.

[EVIL JEDI]

Very simple and helpful guide. Great.