First press tilde (~) to enter the console, then type the following:

angermonsters Angers all monsters (they run around and hunt you down)
aquaticape No target (depending on version)
crazymonsters Berserks all monsters (they run around and kill each other)
freezeworld Freezes world (including you)
give h (0-999) Number of health points given (depending on version)
kill You die
kiwi No clipping
meatwagon Kills all monsters that are currently in the level except bosses (watch out for any spawning monsters, because touching them will instantly kill you)
playbetter God mode
showcoords Display coordinates and camera angle
suckitdown all All weapons, spells, items, and the silver armor
suckitdown armor Silver Armor (1x) Gold Armor (2x)
suckitdown chicken Chicken mode
suckitdown health 100 health
suckitdown lungs Refills oxygen bar when under water
suckitdown mana Refills offensive and defensive mana bars
suckitdown powerup Instant Tome of Power
suckitdown staff Cycles the 3 staff levels
twoweeks Infinite Tome of Power
victor No target or kills all monsters and bosses (depending on version)


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Depending on your Heretic 2 version, the level select code is changelevel or map followed by the following map names:

tutorial Heretic II Training Level
tutorial2 Heretic II Training Level
ssdocks Silverspring Docks
sswarehouse Silverspring Warehouses
sstown The Town of Silverspring
sspalace Silverspring Palace
dmireswamp Darkmire Swamps
andhealer Andoria Healer's Tower
andplaza Andoria Plaza
andslums Andoria Slums
andacademic Andoria Academic Quarters
kellcaves Kell Caves
canyon Katlit'k Canyon
hive1 K'Chekrik Hive
hive2 K'Chekrik Hive 2
gauntlet The Gauntlet
hivetrialpit The Trial Pit
hivepriestess Lair of the Mothers
oglemine1 Ogle Mines
oglemine2 Ogle Mines 2
dungeon Morcalavin's Dungeon
cloudhub Cloud Fortress
cloudquarters Cloud Living Quarters
cloudlabs Cloud Fortress Labs
cloudsanctum Morcalavin's Inner Sanctum


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You can spawn items or monsters into the world by using spawn object, where object is one of the following:

Weapons and offensive spells:
item_weapon_hellstaff Hellstaff
item_weapon_magicmissile Thunder Blast spell
item_weapon_redrain_bow Storm Bow
item_weapon_firewall Firewall spell
item_weapon_phoenixbow Phoenix Bow
item_weapon_sphereofannihilation Sphere of Annihilation spell
item_weapon_maceballs Iron Doom spell
Defensive spells:
item_defense_meteorbarrier Meteor Swarm defensive spell
item_defense_polymorph Morph Ovum defensive spell
item_defense_powerup Not quite the Tome of Power defensive spell (unused)
item_defense_ringofrepulsion Ring of Repulsion defensive spell
item_defense_shield Lightning Shield defensive spell
item_defense_teleport Teleport defensive spell
Health potions:
item_health_full Health Potion
item_health_half Health Vial
Mana stones:
item_mana_combo_half Combo Mana
item_mana_combo_quarter Combo Mana
item_mana_defensive_full Big Defensive Mana
item_mana_defensive_half Small Defensive Mana
item_mana_offensive_full Big Offensive Mana
item_mana_offensive_half Small Offensive Mana
Puzzle items:
item_puzzle_canyonkey Hive key
item_puzzle_cloudkey Fortress key
item_puzzle_cog Cog piece
item_puzzle_crystal Piece of the Sea Crystal
item_puzzle_dungeonkey Dungeon key
item_puzzle_highpriestesskey Key
item_puzzle_highpriestesssymbol T'Chekrik idol
item_puzzle_hive2amulet Warrior's amulet
item_puzzle_hive2gem T'Chekrik heart gem
item_puzzle_hive2spear Spear of the Warrior
item_puzzle_minecartwheel Mine cart wheel
item_puzzle_ore Unrefined ore
item_puzzle_plazacontainer Empty container
item_puzzle_potion Vial of Potion
item_puzzle_refinedore Refined ore
item_puzzle_shield Warrior's Shield
item_puzzle_slumcontainer Container full of Earthblood
item_puzzle_tavernkey Tavern key
item_puzzle_tome Tome of Power (inventory)
item_puzzle_townkey Town key
Monsters: (there should be more though)
monster_assassin Caurthorian Assassin
monster_bee Some sort of flying insect (not used?)
monster_chicken Chicken (they seem to die instantly)
monster_elflord Celestial Watcher (Boss)
monster_fish Myxini (spawning fish on land is pretty funny)
monster_gkrokon G'krokon
monster_gorgon Gorgon
monster_harpy Harpy
monster_imp Flying and shooting pink cube (definitely not used)
monster_morcalavin Morcalavin (Final Boss)
monster_mssithra Giant Ssithra (Boss)
monster_ogle Ogle
monster_plagueElf Plagued Sidhe
monster_rat Rat
monster_seraph_guard Big Seraph Guard
monster_spreader Plague Spreader
monster_ssithra Ssithra Warrior