A C4 will be given to a random Terrorist at the beginning of, in Critical Strike Portable, a Classic match or in Critical Ops, a Defuse match. On the chat, the server will tell all players who has picked up the bomb in this format: "(player name) get Bomb". In Critical Ops the initial bomb carrier's HUD will show "you have the bomb: plant and defend it to win the round".
The C4 can be picked up by other Terrorists if dropped voluntarily or if the bomb carrier dies. In Critical Ops, once picked up by a player, the player's HUD will show "you have picked up the bomb". When planted, every surviving player's HUD will show "the bomb has been planted". If defused, it will show "Counter-Terrorists win".
A C4 can only be planted at a bombsite, except in the case of a Kamikaze in Critical Strike Portable. Once planted, it will detonate after a specific amount of time, at around 40 seconds (depending on the time limit selected in the world in Critical Strike Portable) injuring all players near its blast radius.
To plant a C4, a Terrorist must select it plant it at a bombsite, labelled as A or B and in order to win, must defend it from Counter-Terrorists who want to defuse it. Its detonation time will still pass by, even when all Terrorists are dead. If it is defused, the Counter-Terrorists win. If it explodes, the Terrorists win.
When preparing to detonate, it will make a beeping noise that can be heard by all players at a distance. In Critical Ops, it will simultaneously emit a red flash. Both will increase in tempo the closer to the time it will explode.
- The C4 can be activated outside of the bombsite only by a Kamikaze bot.
- The C4 cannot be defused while reloading.
- The C4 deals damage even to the Terrorists.
- In Critical Strike Portable, after planting the texture changes.
- In Critical Ops, the C4 cannot be defused when reloading.
- When planted it has the same texture as the C4 in Counter-Strike.
- In Critical Strike Portable, there is no draw animation, which means a terrorist can take out the C4 instantly and plant it at a bomb site.
- In Critical Strike Portable, an existing glitch is sometimes the C4 involuntarily duplicates and another Terrorist will pick it up, resulting in two bomb carriers.
- In the Critical Strike Portable tutorial, after planting the bomb as a task, it takes 12 seconds to detonate. When defusing as a task, it takes 39 minutes to detonate.
- In Critical Strike Portable, Counter-Terrorists cannot pick up the C4, except with a glitch.
- To perform it, drop your primary weapon when above the C4 to pick it up. Planting it will defuse the bomb on mobile. Otherwise, it will be planted and defused as normal. This is used as a cheap way to win matches.