code/__DEFINES/combat/attack_types.dm

ATTACK_TYPE_MELEE	Attack was melee, whether or not armed.
ATTACK_TYPE_PROJECTILE	Attack was with a gun or something that should count as a gun (but not if a gun shouldn't count for a gun, crazy right?)
ATTACK_TYPE_UNARMED	Attack was unarmed.. this usually means hand to hand combat.
ATTACK_TYPE_THROWN	Attack was a thrown atom hitting the victim.
ATTACK_TYPE_TACKLE	Attack was a bodyslam/leap/tackle. See: Xenomorph leap tackles.
ATTACK_TYPE_PARRY_COUNTERATTACK	Attack was from a parry counterattack. Do not attempt to parry-this!

Define Details

Attack was melee, whether or not armed.

Attack was from a parry counterattack. Do not attempt to parry-this!

Attack was with a gun or something that should count as a gun (but not if a gun shouldn't count for a gun, crazy right?)

Attack was a bodyslam/leap/tackle. See: Xenomorph leap tackles.

Attack was a thrown atom hitting the victim.

Attack was unarmed.. this usually means hand to hand combat.