Ouch.

code/__DEFINES/combat.dm

@@ -197,3 +197,9 @@ GLOBAL_LIST_INIT(shove_disarming_types, typecacheof(list(
 #define TOTAL_MASS_HAND_REPLACEMENT	5 //standard punching stamina cost. most hand replacements are huge items anyway.
 #define TOTAL_MASS_MEDIEVAL_WEAPON	3.6 //very, very generic average sword/warpick/etc. weight in pounds.
 #define TOTAL_MASS_TOY_SWORD 1.5
+
+//bullet_act() return values
+#define BULLET_ACT_HIT				"HIT"		//It's a successful hit, whatever that means in the context of the thing it's hitting.
+#define BULLET_ACT_BLOCK			"BLOCK"		//It's a blocked hit, whatever that means in the context of the thing it's hitting.
+#define BULLET_ACT_FORCE_PIERCE		"PIERCE"	//It pierces through the object regardless of the bullet being piercing by default.
+#define BULLET_ACT_TURF				"TURF"		//It hit us but it should hit something on the same turf too. Usually used for turfs.

code/__DEFINES/flags.dm

@@ -60,6 +60,7 @@ GLOBAL_LIST_INIT(bitflags, list(1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 204
 #define FLYING (1<<1)
 #define VENTCRAWLING (1<<2)
 #define FLOATING (1<<3)
+#define UNSTOPPABLE		(1<<4)			//When moving, will Bump()/Cross()/Uncross() everything, but won't be stopped.
 
 //Fire and Acid stuff, for resistance_flags
 #define LAVA_PROOF		(1<<0)