Hardcore mode is an alternative to the normal playlists featured in all games since Call of Duty 4: Modern Warfare. As the name suggests, the gameplay is more unforgiving and realistic, making general gameplay more skill-based, with the following implications:
Significantly less health - Players can only withstand 30 damage before dying or going into Last Stand/Final Stand/Second Chance/Dead Man's Hand mode. This practically makes every weapon kill in one or two hits unless losing damage due to bullet penetration.
Limited HUD - The player's HUD is limited to certain objective related things, such as objective markers and whether the player has an enemy flag in Capture the Flag for example. Other things on the HUD are altered from normal play. For instance, when picking up extra ammo with Scavenger the player would receive a vulture icon, with Hardcore mode this symbol is changed to a 'hit marker'. Also, green names are also seen above teammates, but the red text that identifies enemies is absent. Normal HUD features such as the mini-map, ammo counter and equipment slots are missing. The minimap will be available for the duration of a UAV (and its other variants). In some games, the map is available without it in the pause menu as well. In the hardcore Wii version of Call of Duty: World at War, there is a white dot used as a reticle in the game. In Modern Warfare 2, all notifications (upper right corner of the screen) of players calling in or destroying killstreaks, achieving match targets or other notifications such as triple kills are disabled, with the exceptions of enemy players copying their class or destroying their tactical insertion.
Friendly Fire on - Teammates can be damaged and killed. Deliberate team-killers are punished; in Call of Duty 4: Modern Warfare and Call of Duty: Modern Warfare 2, a player is automatically killed and sat out for a period of time after 3 or more team-kills (in the latter, certain actions such as killing the team with a launcher in the start of a round can lead to harsher penalties). Additionally, a player-controlled Killstreak ends prematurely if the penalty is given. In Call of Duty: World at War, Call of Duty: Black Ops, Call of Duty: Black Ops II, Call of Duty: Black Ops III and Call of Duty: WWII, the player is automatically kicked out of the game (and is banned from joining the session) after three team-kills. In Call of Duty: Black Ops II, if the player does this too many times, they will be placed in "probation" which temporary disables the player from joining any match. Some Killstreak/Scorestreak kills do not count towards a kick, a notable example being the Warthog. In Call of Duty: Mobile, Call of Duty: Modern Warfare and Call of Duty: Vanguard, after two team-kills, each shot on a teammate will result in reflection of damage, effectively killing that player, but that player will not be placed on a timeout or get kicked out of the session.
In Call of Duty: Modern Warfare 2, Call of Duty: Modern Warfare 3, Call of Duty: Ghosts and Call of Duty: Infinite Warfare, an option called Hardcore Ricochet is available, which replaced most of the Hardcore playlists. Friendly fire is still enabled, but in the matter that the damage done to teammates is inflicted towards the player with no damage done to the teammate shot.
1 Game Modes Available
1.1 Call of Duty 4: Modern Warfare
1.2 Call of Duty: World at War
1.3 Call of Duty: Modern Warfare 2
1.4 Call of Duty: Black Ops
1.5 Call of Duty: Modern Warfare 3
1.6 Call of Duty: Black Ops II
1.7 Call of Duty: Ghosts
1.8 Call of Duty: Advanced Warfare
1.9 Call of Duty: Black Ops III
1.10 Call of Duty: Infinite Warfare
1.11 Call of Duty: Modern Warfare Remastered
1.12 Call of Duty: WWII
1.13 Call of Duty: Mobile
1.14 Call of Duty: Vanguard
1.15 Call of Duty: Modern Warfare III
1.16 Call of Duty: Black Ops 6
1.17 Call of Duty: Black Ops 7
1.18 Call of Duty: Modern Warfare 4
2 Gallery
3 Video
4 Trivia
5 References
Game Modes Available[]
Call of Duty 4: Modern Warfare[]
Hardcore Team Deathmatch
Hardcore Search and Destroy
Hardcore Headquarters
Call of Duty: World at War[]
Hardcore Team Deathmatch
Hardcore Search and Destroy
Hardcore War
Hardcore Headquarters
Hardcore Free-for-All
Hardcore Capture the Flag
Call of Duty: Modern Warfare 2[]
Hardcore Team Deathmatch
Hardcore Capture the Flag
Hardcore Ricochet: S&D
Hardcore Ricochet:HQ Pro
Hardcore Mosh Pit
Call of Duty: Black Ops[]
Hardcore Team Deathmatch
Hardcore Search and Destroy
Hardcore Free-for-All
Hardcore Headquarters
Hardcore Capture the Flag
Call of Duty: Modern Warfare 3[]
Hardcore Ricochet: Team Deathmatch
Hardcore Ricochet: Search and Destroy
Hardcore Ricochet: HQ Pro
Hardcore Ricochet: Kill Confirmed
Hardcore Ricochet: Domination
Hardcore Free for All
Call of Duty: Black Ops II[]
Hardcore Team Deathmatch
Hardcore Search and Destroy
Hardcore Capture the Flag
Hardcore Kill Confirmed
Hardcore Domination
Call of Duty: Ghosts[]
Hardcore Team Deathmatch
Hardcore Search and Rescue
Hardcore Kill Confirmed
Hardcore Domination
Call of Duty: Advanced Warfare[]
Hardcore Team Deathmatch
Hardcore Domination
Hardcore Kill Confirmed
Hardcore Search and Destroy
Hardcore Mosh Pit
Call of Duty: Black Ops III[]
Hardcore Team Deathmatch
Hardcore Free-for-All
Hardcore Domination
Source: https://callofduty.fandom.com/wiki/Hardcore. This is an independent Call of Duty: Modern Warfare 4 reference page.