[CaRa]

Код:

 if (strcmp("/heal", cmdtext, true, 5) == 0)
        {
                SetPlayerHealth(playerid, 100);
                SetPlayerArmour(playerid, 100);
                SendClientMessage(playerid, 0x0FFDD349, "pm>>Your health and armor have been fully restored.");
                return 1;
        }

Код:

 if (strcmp("/kill", cmdtext, true, 5) == 0)
        {
            SetPlayerHealth(playerid, 0);
            return 1;
        }

You forgot to put return 1; and for command /kill you haved SetPlayerHealth(playerid, 100); wich increase you're health not killing you