Skin Deep runs on the Doom 3 engine. As such, a lot of the same console commands and cheats from that game also work in this one. To open the console, simply press the tilde key (~) (no launch options needed!).

This is not an exhaustive list of all console commands! I've omitted anything that will just outright crash the game. This should get you started though. If something isn't listed, and you feel like really digging into the console, you can type listcmds in the console or search online for "Doom 3 Console Commands".

god - Grants invincibility
give ammo - Max Ammo
give armor - Max Armor
give health - Max Health
give all - Max ammo and armor
noclip - Lets you pass through walls
notarget - Grants invisiblity
killEntity - Deletes whatever the player is aiming at
killmonsters - Removes all enemies from the level
kill - Gives Nina a permanent vacation
debugSetCombatState 1/0 - Sets combat state on/off
debugFuseboxCodes - Lists all Fusebox codes generated for the current level
debugNotesReadAll - Adds all notes for the current level to your Memory Palace
debugFuseboxUnlockAll - Unlocks all fuseboxes
debugEscalation - Advances to the next mission objective
saveGame - Quicksaves the game
debugEndMission / impulse 25 - Completes the level
map - Resets the level
quit - When you don't feel like pressing Alt+F4

give weapon_autopistol / give ammo_autopistol_mag
give weapon_rifle / give ammo_rifle_box
give weapon_shotgun / give ammo_shotgun_box

spawn moveable_item_wiregrenade
spawn moveable_item_tnt
spawn moveable_item_telegun
spawn moveable_item_seekergrenade
spawn moveable_item_hackgrenade
spawn moveable_item_empgrenade
spawn moveable_item_chembomb
spawn moveable_gascylinder
spawn moveable_gascylinder_small
spawn moveable_item_baffler
spawn moveable_banana
spawn moveable_soap
spawn moveable_pepperbag_small

spawn item_cat_key
spawn item_securitycard_blue
spawn item_securitycard_yellow
spawn item_securitycard_shipkey

spawn moveable_walkie_talkie
spawn moveable_duper
spawn moveable_item_signallamp
spawn moveable_deodorant
spawn moveable_basketball
spawn moveable_burger

spawn monster_dummybot
spawn monster_zena - Your clone. Copies your movement.
spawn monster_cat_big - A giant room-filling cat.
spawn monster_bodyguard - A friendly pirate that enemies will target, but won't help in any way.
spawn monster_boss - A pirate with 20hp.
spawn monster_bossfloater - A pirate with 50 hp that floats through the air.
spawn monster_cat - Try shooting it. I dare you.
spawn monster_dozerbot
spawn monster_engineer
spawn monster_engineer_b
spawn monster_heavy
spawn monster_repairbot
spawn monster_spearbot
spawn monster_thug
spawn monster_thug_b
spawn monster_turret

spawn monster_mech

map vig_tutorial.map - CSS Wobbegong, Junker Barge
map vig_hub.map - Nina's Habitat (use noclip to visit the various training rooms!)
map sh_laundromat01.map - Periwinkle, Laundromat Barge
map sh_lighthouse01.map - Angler, Lighthouse Station
map vig_surveil.map - Asteroid 92, The Stakeout
map sh_observatory01.map - Stargazer, Observatory Vessel
map sh_library01.map - Herring, Library Freighter
map vig_penthouse.map - Celestial Penthouse, Little Lion Returns
map sh_restaurant01.map - Remora, Restaurant Ferry
map sh_radio01.map - Narhwal, Radio Station
map sh_windfarm01.map - Barreleye - Wind Farm Tanker
map sh_postoffice01.map - Fugu, Post Office Barge
map vig_convention.map - Dentist Convention, Planting The Bug
map sh_vault01.map - Chiton, Secured Vault Freighter
map sh_mining01.map - Portunid, Mining Tanker
map sh_mechrepair01.map - Beluga, Mech Repair Frigate
map sh_cargo01.map - Minnow - Icebreaker Vessel
map sh_cargo02.map - Guppy, Algae Refinery Tanker
map vig_miaocorp.map - MiaoCorp, Performance Review
map vig_lionship.map - Wonky Space, Assault on Good Twin Castle
map vig_memories.map - Good Twin Castle, The Zena Zone
map vig_beachparty.map - The Beach, Beach Episode
map vig_credits.map - Credits Chamber, The Implementors

map test0.map - Empty test room
map itemzoo.map - Item test room
map particlezoo.map - Particle test room. Neat!
map propzoo.map - Prop test room
map propzoo2.map - Another prop test room.

impulse 13 - Make Nina fall over
impulse 20 - Lock/unlock all airlocks
impulse 21 - Ride whoever the player is aiming at
impulse 23 - Initiate vent-purge
impulse 32 - Start radio check-in
pm_thirdperson 1 - Enables the 3rd Person camera.
condump [filename] - Dumps the current contents of the console to a .txt file in the Skin Deep userdata folder.
debugClearAchievements - Reset Steam achievements.

• Everyone at Blendo Games for making Skin Deep.
  
• John Carmack, for open-sourcing the Doom 3 engine and inventing the Carmack Smack.
  
• And You! For reading this guide.