Skill level

Skill level determines the overall difficulty of a game: for instance, how many weapons and powerups are encountered, how much ammo various items give, and monster populations and behavior. There are five settings.

Doom skill levels

 * 1) Skill levels of the same class have the same number and same types of monsters and items. The difference mainly amounts to larger and tougher detachments of monsters on the harder skill levels, but not always; for example, in E3M6: Mt. Erebus the blue key is located in different places depending on the skill level.
 * 2) Ammo powerups give twice as much ammunition as they do on other skill levels.
 * 3) Killed monsters (apart from the ones spawned by the spawn shooter) respawn at their original starting point where possible. This happens after a randomized time delay (roughly 8 seconds to 5 minutes). Respawned monsters are instantly aroused and advance on the player. The respawn modifier can be used with any skill level using the -respawn command line parameter. See also (0,0) respawning bug.
 * 4) All monsters attack more often, Demons and Spectres move and attack 2 × faster, Imp fireballs are 50% faster, and Cacodemon, Hell Knight, and Baron of Hell projectiles are 33% faster. This modifier can be used with any skill level using the -fast command line parameter. See also IDCLEV idiosyncrasies.
 * 5) All cheat codes except idclev and iddt are disabled.