- Final interactions
Successfully complete the game. Then, go to one of the following locations to find the corresponding character(s) and have a final interaction with them:

Lita	In front of Lars's tombstone at the cemetery. There will be a brief cutscene where you share a moment of silence with her. The moment will last and the time of day will shift until you press [Interact] again.
Mangus	On top of the large sword in Blade Henge. Notice
Rima	On top of her tower in the jungle
Ophelia	In front of the large stone cross near The Hunter in the Grasslands (located to the left of the huge sword on the map). Eddie will ask if she wants to make out. A cutscene will play of the two kissing until you press [Interact] again.
Fire Baron	In the jungle directly north of the tree island at the bottom of the last continent. He is to the left of the main road as soon as it turns, traveling south to east.
Infantry/Army	At the Beach Party
Thunderhogs	At the Kill Master's Lair. You can drink with his bassists and comment on Lemmy's bass playing ability.

- Extra nitrous power
Successfully complete all Racing secondary missions to get increased nitrous power.

- Achievements
Do the following things to obtain the corresponding Gamerscore points:

5 Points
One Hit Wonder	Purchased 1 upgrade in the Motor Forge.
10 Points
Victör	Won a ranked multiplayer match.
Serpent Samaritan	Freed 40 Bound Serpents.
Silence, groundwalker!	Gained 5 or more seconds of hang time in a single jump - any mode.
Practice Bloody Practice	Won an AI Stage Battle - any difficulty.
15 Points
Got a Car and a Date	Finishd 'Welcome to the Age of Metal'.
Dollpocalypse	Hit 6 enemies with the explosion from a Brood's Double Team.
Death From Above	Killed 20 enemies with one Bleeding Death.
Serpent Spanker	Freed 80 Bound Serpents.
Begin a Revolution	Finishd 'Exploited in the Bowels of Hell'.
Coolest Thing Ever	Jumped over a Hextadon in the Deuce.
French Kiss Instructor	Finishd 'Pilgrimage of Screams'.
Chicks n' Booze n' Stuff	Finishd 'Sanctuary of Sin'.
Hair Remover	Finishd 'Battle for Bladehenge'.
No More Tears	Finishd 'Sea of Black Tears'.
Euthanasia	Hit 15 enemies with one Agony Ball using the Pain Lifter's Double Team.
Beast Master	Rode every animal in the world.
Fistfull of Fog	Finishd 'Dry Ice, Wet Graves'.
Six Degrees of Schafer	Played with or against another player who has this Achievement.
Ran to the Hills	Finishd 'It's Raining Death'.
Ringleader	Trapped 15 enemies in one ring of fire with the Fire Baron's Double Team.
Painkiller	Killed 25 enemies with the grinder of one Rock Crusher.
Thick as a Baby's Arm	Finishd 'Lair of the Metal Queen'.
20 Points
Master of the Blood	Double Teamed with every Tainted Coil unit.
Tourist	Watched all vistas.
Master of the Flame	Double Teamed with every Ironheade unit.
Iron Fist	Won an AI Stage Battle - Brutal difficulty.
Overkill	Finishd all hunting secondary missions.
Squeal Like a Chicken	Finishd all racing secondary missions.
Virtuoso	Learned all guitar solos.
Voices From Beyond	Unlocked all songs in the Mouth of Metal.
Now You Must Tell the Tale	Watch all Legends.
Armchair General	Won a Stage Battle by yourself against the AI without attacking.
Flowerslave	Summoned all Motor Forges.
Master of the Tear	Double Teamed with every Drowning Doom unit.
Some Demon Flesh on your Bumper	Slayed 150 enemies with the Deuce - any mode.
Subjügator	Won 10 ranked multiplayer matches.
Protector	Finishd 20 ambush, outpost defense, or mortar secondary missions.
Quill Tosser	Killed a Tollusk using only Ground Urchins.
25 Points
Legend	Finishd Campaign mode on Brutal.
Loyal Customer	Purchased all upgrades in the Motor Forge.
Roadie	Finishd Campaign mode on Normal Difficult Level.
Serpent Savior	Freed all 120 Bound Serpents.
Groupie	Finishd Campaign mode on Easy Difficult Level.
30 Points
Sellout	Spent 250,000 fans - any mode.
I've never touched an axe before	Personally smote 300 enemies - any mode.
Favored	Acquired 3,000 Fire Tributes.
50 Points
Metal God	Achieved 100% completion on the stats screen.
Boar Bather	Rode a Razorfire Boar into the Sea of Black Tears and live to tell the tale.
Cönquerer	Won 50 ranked multiplayer matches.

10 Points
Beard Beard Action Beard!	Make out with Ophelia while wearing the Mountain Man Threads.
A Face Like a Beast	Kill 15 enemies with a Metal Beast while wearing the Zaulia Threads.
Hammer of Infinite Fate Tourist	Play a multiplayer game on all Hammer of Infinite Fate multiplayer maps.
Whispering Rock	Chisel four Razputin heads onto Mt. Rockmore.
Hammer of Fate Champion	Be victorious in 10 games on Hammer of Infinite Fate maps - ranked or vs. the Brütal AI.
Carnivore	Run down 20 animals in the Deuce with the Coiling Maw equipped.
If You Want Blood, You Got It	Kill 20 Tainted Coil units with the Disgorger.
Cry Me a River	Kill 20 Drowning Doom units with the Eye of Sorrow.
Norwegian Sendoff	Visit the grave of a fallen hero while wearing the Black Metal Threads.

- Spike-Quilled Axe
Successfully complete all Hunter secondary missions to unlock the Spike-Quilled Axe. Notice: The Hunter is located near the large stone cross in the Grasslands, and he will move halfway through his missions to the Ice Barracks. Once you complete all Hunter secondary missions, return to the first place you met him, and he will give you the Steel-Quill Axe.

- Rob Halford reference
Rob Halford plays General Lyonwhite even though his last name is Lita and Lars'.

- Riding the animals
All animals as big as Eddie or larger can be ridden. Hit a creature with a bolt of lightning to stun them. Then, get near them, and press Y. While riding them, press A to perform an attack specific to that creature. Raptor Elk and Tullusks are a couple examples of creatures with melee attacks, while the Laser Panther shoots lasers from its eyes. The large wooden horse creatures in the final map area (with large swinging axes for tails) can also be ridden.

- Psychonauts reference
In the first cutscene, where you are given the options to toggle the blood gore and swearing, just before Eddie says the line that leads to the option of turning on or off swearing, he sees one of the band members dancing on a very shaky ledge. While that band member is dancing on that ledge, he will be chanting a song that was originally done in Psychonauts by some kids in a few parts, but most notably by Raz himself in the level where you have to fight four wrestlers to get a card. At the end of each match after they were defeated, Raz did the same dance and chant song.


The headbanger that wears the goggles at all the Death Rack missions sounds identical to Raz, but slightly deeper.

- Kyle Gass reference
The man at the Mortar missions has the same facial features, hair, and voice as Kyle Gass. Kyle Gass is the lead guitarist and vocalist of Tenacious D and the Godfather of Jack Black's son. -From: Tyler Murphy