This is a very rudimentary guide about all of the ways you can possibly damage a player in GKC and how customizable it is. I will also rate the damage method on a scale of 1 - 10 based on customizability and applicable situations.
Player to Player / Weapon to Player
This part is essentially common knowledge. A player can damage another through weapons with weapons dealing amounts kinds of damage. A full table of the damage amounts of certain weapon was posted by @JoeTheChicken
[đź“ś] The Ultimate Guide for EVERY WEAPON
Player to Player damage is only really applicable in situations where you want the players to attack each other in games like battle royale or capture the flag. Damage is also limited to the set damage values for the weapons
Customizability (5)
Applicable Situations (7)
Overall (6)
Laser to Player
Laser to Player is a Highly versatile system with fully customizable damage numbers. The few downsides of this is that Laser to Player is immobile reducing the applicable situations. This form of damage is used in landmines or one way out games.
Customizability (10)
Applicable Situations (7)
Overall (8.5)
Sentry to Player / Weapon to Player
Sentry to player is another form of Weapon to Player damage similar to Player to Player where the damage is limited to the weapon. A sentry is a AI player that attacks the player using a weapon. This is only applicable in a few games with boss fights and other things due to sentries being immobile.
Customizability (5)
Applicable Situations (3)
Overall (4)
Pseudo Health / Negative Health Granters (Concept)
I will not go into detail on this as there is already a guide on it by @I-am-helpful featured here:
Pseudo-Health, what it does, how to use it (Difficulty: đźź©)
The idea is a separate health separate from the GKC health allowing you full flexibility allowing you to grant negative health on the go. This can be used in poisonous fogs in battle royale and any other situation where damage is needed. This system lacks in the feel of taking damage though without the damage indicators such as the screen turning red or blue.
Customizability (10)
Applicable Situations (10)
Overall (8)
PROBLEMS
Unfortunately, Negative health granters do not exist meaning that we cannot customize health completely freely.
SUMMARY
Overall there are several great ways to deal damage to players. The best choices for damage are Player to Player or Laser to Player depending on what you need.