diff --git a/source/client.qc b/source/client.qc
index e0b783c..5c52d9b 100644
--- a/source/client.qc
+++ b/source/client.qc
@@ -1080,10 +1080,10 @@ void() cheat = {
 		return;
 	}
 
-	self.ammo_rockets = 100;
-	self.ammo_nails   = 200;
-	self.ammo_shells  = 100;
-	self.ammo_cells   = 200;
+	self.ammo_cells   = AMMAX_CELLS;
+	self.ammo_nails   = AMMAX_NAILS;
+	self.ammo_rockets = AMMAX_ROCKETS;
+	self.ammo_shells  = AMMAX_SHELLS;
 
 	self.items |= IT_AXE |
 	              IT_SHOTGUN |
@@ -1394,7 +1394,7 @@ float(entity targ, entity attacker) obit_monster = {
 
 float(entity targ, entity attacker) obit_falling = {
 	if(targ.deathtype == "falling") {
-		targ.deathtype = "";
+		targ.deathtype = string_null;
 		if(targ.pronoun == PRO_NONE) {
 			bprint(" hit the ground too hard\n");
 		} else {
diff --git a/source/defs.qc b/source/defs.qc
index edf4244..f0bc3b8 100644
--- a/source/defs.qc
+++ b/source/defs.qc
@@ -275,6 +275,11 @@ const vector VEC_ORIGIN = '0 0 0';
 
 const float BODYQUE_MAX = 16;
 
+const float AMMAX_CELLS   = 100;
+const float AMMAX_NAILS   = 200;
+const float AMMAX_ROCKETS = 100;
+const float AMMAX_SHELLS  = 100;
+
 const string WEPNAME_AXE              = "Axe";
 const string WEPNAME_SHOTGUN          = "Shotgun";
 const string WEPNAME_SUPER_SHOTGUN    = "Double-barrelled Shotgun";
@@ -554,11 +559,25 @@ enum {
 };
 
 enum {
-	SF_CHEATS    = 1 << 0,
+	AMTYPE_SHELLS = 1,
+	AMTYPE_NAILS,
+	AMTYPE_ROCKETS,
+	AMTYPE_CELLS,
+};
+
+enum {
+	SIGIL_1 = 1,
+	SIGIL_2 = 2,
+	SIGIL_3 = 4,
+	SIGIL_4 = 8,
+};
+
+enum {
+	SF_CHEATS    = 1,
 	SF_LIVES_BEG = 1,
 	SF_LIVES_END = 3,
-	SF_LIVES_MSK = 0x0E,
-	SF_DIST_AMMO = 1 << 4,
+	SF_LIVES_MSK = 14,
+	SF_DIST_AMMO = 16,
 };
 #pragma noref 0
 
diff --git a/source/doors.qc b/source/doors.qc
index d830f5d..2a43017 100644
--- a/source/doors.qc
+++ b/source/doors.qc
@@ -128,9 +128,9 @@ void() door_fire = {
 void() door_use = {
 	entity oself;
 
-	self.message = ""; // door message are for touch only
-	self.owner.message = "";
-	self.enemy.message = "";
+	self.message = string_null; // door message are for touch only
+	self.owner.message = string_null;
+	self.enemy.message = string_null;
 	oself = self;
 	self = self.owner;
 	door_fire();
@@ -181,7 +181,7 @@ void() door_touch = {
 
 	self.owner.attack_finished = time + 2;
 
-	if(self.owner.message != "") {
+	if(self.owner.message != string_null) {
 		centerprint(other, self.owner.message);
 		sound(other, CHAN_VOICE, "misc/talk.wav", 1, ATTN_NORM);
 	}
@@ -287,7 +287,7 @@ void() LinkDoors = {
 		if(self.targetname) {
 			starte.targetname = self.targetname;
 		}
-		if(self.message != "") {
+		if(self.message != string_null) {
 			starte.message = self.message;
 		}
 		t = find(t, classname, self.classname);
diff --git a/source/items.qc b/source/items.qc
index 3ba95f5..bf23253 100644
--- a/source/items.qc
+++ b/source/items.qc
@@ -97,16 +97,13 @@ HEALTH BOX
 // "ignore" will ignore max_health limit
 //
 float(entity e, float healamount, float ignore) T_Heal = {
-	if(e.health <= 0) {
-		return 0;
-	}
-	if((!ignore) && (e.health >= other.max_health)) {
+	if(e.health <= 0 || (!ignore && e.health >= other.max_health)) {
 		return 0;
 	}
 	healamount = ceil(healamount);
 
 	e.health = e.health + healamount;
-	if((!ignore) && (e.health >= other.max_health)) {
+	if(!ignore && e.health >= other.max_health) {
 		e.health = other.max_health;
 	}
 
@@ -161,16 +158,11 @@ void() health_touch = {
 	}
 
 	if(self.healtype == 2) { // Megahealth? Ignore max_health...
-		if(other.health >= 250) {
-			return;
-		}
-		if(!T_Heal(other, self.healamount, 1)) {
-			return;
-		}
-	} else {
-		if(!T_Heal(other, self.healamount, 0)) {
+		if(other.health >= 250 || !T_Heal(other, self.healamount, TRUE)) {
 			return;
 		}
+	} else if(!T_Heal(other, self.healamount, FALSE)) {
+		return;
 	}
 
 	sprint(other, "You receive ", ftos(self.healamount),  " health\n");
@@ -232,28 +224,28 @@ ARMOR
 void() armor_touch = {
 	float type, value, bit;
 
-	if(other.health <= 0) {
-		return;
-	}
-	if(other.classname != "player") {
+	if(other.health <= 0 || other.classname != "player") {
 		return;
 	}
 
-	if(self.classname == "item_armor1") {
-		type = 0.3;
-		value = 100;
-		bit = IT_ARMOR1;
-	}
-	if(self.classname == "item_armor2") {
-		type = 0.6;
-		value = 150;
-		bit = IT_ARMOR2;
-	}
-	if(self.classname == "item_armorInv") {
-		type = 0.8;
-		value = 200;
-		bit = IT_ARMOR3;
+	switch(self.classname) {
+		case "item_armor1":
+			type = 0.3;
+			value = 100;
+			bit = IT_ARMOR1;
+			break;
+		case "item_armor2":
+			type = 0.6;
+			value = 150;
+			bit = IT_ARMOR2;
+			break;
+		case "item_armorInv":
+			type = 0.8;
+			value = 200;
+			bit = IT_ARMOR3;
+			break;
 	}
+
 	if(other.armortype * other.armorvalue >= type * value) {
 		return;
 	}
@@ -323,42 +315,32 @@ WEAPONS
 ===============================================================================
 */
 
-void() bound_other_ammo = {
-	if(other.ammo_shells > 100) {
-		other.ammo_shells = 100;
+void(entity e) bound_ammo = {
+	if(e.ammo_shells > AMMAX_SHELLS) {
+		e.ammo_shells = AMMAX_SHELLS;
 	}
-	if(other.ammo_nails > 200) {
-		other.ammo_nails = 200;
+	if(e.ammo_nails > AMMAX_NAILS) {
+		e.ammo_nails = AMMAX_NAILS;
 	}
-	if(other.ammo_rockets > 100) {
-		other.ammo_rockets = 100;
+	if(e.ammo_rockets > AMMAX_ROCKETS) {
+		e.ammo_rockets = AMMAX_ROCKETS;
 	}
-	if(other.ammo_cells > 100) {
-		other.ammo_cells = 100;
+	if(e.ammo_cells > AMMAX_CELLS) {
+		e.ammo_cells = AMMAX_CELLS;
 	}
 };
 
 
 float(float w) RankForWeapon = {
-	if(w == IT_LIGHTNING) {
-		return 1;
+	switch(w) {
+		case IT_LIGHTNING:        return 1;
+		case IT_ROCKET_LAUNCHER:  return 2;
+		case IT_SUPER_NAILGUN:    return 3;
+		case IT_GRENADE_LAUNCHER: return 4;
+		case IT_SUPER_SHOTGUN:    return 5;
+		case IT_NAILGUN:          return 6;
+		default:                  return 7;
 	}
-	if(w == IT_ROCKET_LAUNCHER) {
-		return 2;
-	}
-	if(w == IT_SUPER_NAILGUN) {
-		return 3;
-	}
-	if(w == IT_GRENADE_LAUNCHER) {
-		return 4;
-	}
-	if(w == IT_SUPER_SHOTGUN) {
-		return 5;
-	}
-	if(w == IT_NAILGUN) {
-		return 6;
-	}
-	return 7;
 };
 
 /*
@@ -393,62 +375,66 @@ void() weapon_touch = {
 		return;
 	}
 
-	// if the player was using their best weapon, change up to the new one if better
+	// if the player was using their best weapon, change up to the new one if
+	// better
 	stemp = self;
 	self = other;
 	best = W_BestWeapon();
 	self = stemp;
 
-	if(deathmatch == 2 || coop) {
-		leave = 1;
-	} else {
-		leave = 0;
-	}
+	leave = (deathmatch == 2 || coop);
 
-	if(self.classname == "weapon_nailgun") {
-		if(leave && (other.items & IT_NAILGUN)) {
-			return;
-		}
-		hadammo = other.ammo_nails;
-		new = IT_NAILGUN;
-		other.ammo_nails = other.ammo_nails + 30;
-	} else if(self.classname == "weapon_supernailgun") {
-		if(leave && (other.items & IT_SUPER_NAILGUN)) {
-			return;
-		}
-		hadammo = other.ammo_rockets;
-		new = IT_SUPER_NAILGUN;
-		other.ammo_nails = other.ammo_nails + 30;
-	} else if(self.classname == "weapon_supershotgun") {
-		if(leave && (other.items & IT_SUPER_SHOTGUN)) {
-			return;
-		}
-		hadammo = other.ammo_rockets;
-		new = IT_SUPER_SHOTGUN;
-		other.ammo_shells = other.ammo_shells + 5;
-	} else if(self.classname == "weapon_rocketlauncher") {
-		if(leave && (other.items & IT_ROCKET_LAUNCHER)) {
-			return;
-		}
-		hadammo = other.ammo_rockets;
-		new = IT_ROCKET_LAUNCHER;
-		other.ammo_rockets = other.ammo_rockets + 5;
-	} else if(self.classname == "weapon_grenadelauncher") {
-		if(leave && (other.items & IT_GRENADE_LAUNCHER)) {
-			return;
-		}
-		hadammo = other.ammo_rockets;
-		new = IT_GRENADE_LAUNCHER;
-		other.ammo_rockets = other.ammo_rockets + 5;
-	} else if(self.classname == "weapon_lightning") {
-		if(leave && (other.items & IT_LIGHTNING)) {
-			return;
-		}
-		hadammo = other.ammo_rockets;
-		new = IT_LIGHTNING;
-		other.ammo_cells = other.ammo_cells + 15;
-	} else {
-		objerror("weapon_touch: unknown classname");
+	switch(self.classname) {
+		case "weapon_nailgun":
+			if(leave && other.items & IT_NAILGUN) {
+				return;
+			}
+			hadammo = other.ammo_nails;
+			new = IT_NAILGUN;
+			other.ammo_nails = other.ammo_nails + 30;
+			break;
+		case "weapon_supernailgun":
+			if(leave && other.items & IT_SUPER_NAILGUN) {
+				return;
+			}
+			hadammo = other.ammo_rockets;
+			new = IT_SUPER_NAILGUN;
+			other.ammo_nails = other.ammo_nails + 30;
+			break;
+		case "weapon_supershotgun":
+			if(leave && other.items & IT_SUPER_SHOTGUN) {
+				return;
+			}
+			hadammo = other.ammo_rockets;
+			new = IT_SUPER_SHOTGUN;
+			other.ammo_shells = other.ammo_shells + 5;
+			break;
+		case "weapon_rocketlauncher":
+			if(leave && other.items & IT_ROCKET_LAUNCHER) {
+				return;
+			}
+			hadammo = other.ammo_rockets;
+			new = IT_ROCKET_LAUNCHER;
+			other.ammo_rockets = other.ammo_rockets + 5;
+			break;
+		case "weapon_grenadelauncher":
+			if(leave && other.items & IT_GRENADE_LAUNCHER) {
+				return;
+			}
+			hadammo = other.ammo_rockets;
+			new = IT_GRENADE_LAUNCHER;
+			other.ammo_rockets = other.ammo_rockets + 5;
+			break;
+		case "weapon_lightning":
+			if(leave && other.items & IT_LIGHTNING) {
+				return;
+			}
+			hadammo = other.ammo_rockets;
+			new = IT_LIGHTNING;
+			other.ammo_cells = other.ammo_cells + 15;
+			break;
+		default:
+			objerror("weapon_touch: unknown classname");
 	}
 
 	sprint(other, "You got the ", self.netname, "\n");
@@ -759,13 +745,9 @@ void() key_touch = {
 	entity stemp;
 	float best;
 
-	if(other.classname != "player") {
-		return;
-	}
-	if(other.health <= 0) {
-		return;
-	}
-	if(other.items & self.items) {
+	if(other.classname != "player" ||
+	   other.health <= 0 ||
+	   other.items & self.items) {
 		return;
 	}
 
@@ -884,10 +866,7 @@ void() sigil_touch = {
 	entity stemp;
 	float best;
 
-	if(other.classname != "player") {
-		return;
-	}
-	if(other.health <= 0) {
+	if(other.classname != "player" || other.health <= 0) {
 		return;
 	}
 
@@ -898,7 +877,7 @@ void() sigil_touch = {
 	self.solid = SOLID_NOT;
 	self.model = string_null;
 	serverflags = serverflags | (self.spawnflags & 15);
-	self.classname = ""; // so rune doors won't find it
+	self.classname = string_null; // so rune doors won't find it
 
 	activator = other;
 	SUB_UseTargets(); // fire all targets / killtargets
@@ -917,19 +896,19 @@ void() item_sigil = {
 	precache_sound("misc/runekey.wav");
 	self.noise = "misc/runekey.wav";
 
-	if(self.spawnflags & 1) {
+	if(self.spawnflags & SIGIL_1) {
 		precache_model("progs/end1.mdl");
 		setmodel(self, "progs/end1.mdl");
 	}
-	if(self.spawnflags & 2) {
+	if(self.spawnflags & SIGIL_2) {
 		precache_model2("progs/end2.mdl");
 		setmodel(self, "progs/end2.mdl");
 	}
-	if(self.spawnflags & 4) {
+	if(self.spawnflags & SIGIL_3) {
 		precache_model2("progs/end3.mdl");
 		setmodel(self, "progs/end3.mdl");
 	}
-	if(self.spawnflags & 8) {
+	if(self.spawnflags & SIGIL_4) {
 		precache_model2("progs/end4.mdl");
 		setmodel(self, "progs/end4.mdl");
 	}
@@ -951,10 +930,7 @@ void() powerup_touch = {
 	entity stemp;
 	float best;
 
-	if(other.classname != "player") {
-		return;
-	}
-	if(other.health <= 0) {
+	if(other.classname != "player" || other.health <= 0) {
 		return;
 	}
 
@@ -962,8 +938,8 @@ void() powerup_touch = {
 
 	if(deathmatch) {
 		self.mdl = self.model;
-		if((self.classname == "item_artifact_invulnerability") ||
-				(self.classname == "item_artifact_invisibility")) {
+		if(self.classname == "item_artifact_invulnerability" ||
+		   self.classname == "item_artifact_invisibility") {
 			self.nextthink = time + 60 * 5;
 		} else {
 			self.nextthink = time + 60;
@@ -1104,17 +1080,18 @@ void() BackpackTouch = {
 		sprint(other, "the ", self.netname);
 	}
 
-	// if the player was using their best weapon, change up to the new one if better
+	// if the player was using their best weapon, change up to the new one if
+	// better
 	stemp = self;
 	self = other;
 	best = W_BestWeapon();
 	self = stemp;
 
 	// change weapons
-	other.ammo_shells = other.ammo_shells + self.ammo_shells;
-	other.ammo_nails = other.ammo_nails + self.ammo_nails;
+	other.ammo_shells  = other.ammo_shells  + self.ammo_shells;
+	other.ammo_nails   = other.ammo_nails   + self.ammo_nails;
 	other.ammo_rockets = other.ammo_rockets + self.ammo_rockets;
-	other.ammo_cells = other.ammo_cells + self.ammo_cells;
+	other.ammo_cells   = other.ammo_cells   + self.ammo_cells;
 
 	new = self.items;
 	if(!new) {
@@ -1226,14 +1203,14 @@ entity() DropBackpack = {
 			item.netname = WEPNAME_LIGHTNING;
 			break;
 		default:
-			item.netname = "";
+			item.netname = string_null;
 			break;
 	}
 
-	item.ammo_shells = self.ammo_shells;
-	item.ammo_nails = self.ammo_nails;
+	item.ammo_shells  = self.ammo_shells;
+	item.ammo_nails   = self.ammo_nails;
 	item.ammo_rockets = self.ammo_rockets;
-	item.ammo_cells = self.ammo_cells;
+	item.ammo_cells   = self.ammo_cells;
 
 	item.velocity_z = 300;
 	item.velocity_x = -100 + (random() * 200);
diff --git a/source/oldone.qc b/source/oldone.qc
index 3c64aec..869657f 100644
--- a/source/oldone.qc
+++ b/source/oldone.qc
@@ -112,7 +112,7 @@ void() finale_1 = {
 	remove(pl);
 
 	WriteByte(MSG_ALL, SVC_FINALE);
-	WriteString(MSG_ALL, "");
+	WriteString(MSG_ALL, string_null);
 
 	pl = find(world, classname, "player");
 	while(pl != world) {
diff --git a/source/player.qc b/source/player.qc
index aaf407d..5e0d265 100644
--- a/source/player.qc
+++ b/source/player.qc
@@ -284,7 +284,7 @@ void() PainSound = {
 
 	rs = rint((random() * 5) + 1);
 
-	self.noise = "";
+	self.noise = string_null;
 	if(rs == 1) {
 		self.noise = "player/pain1.wav";
 	} else if(rs == 2) {
@@ -504,7 +504,7 @@ void() PlayerDie = {
 		DropBackpack();
 	}
 
-	self.weaponmodel = "";
+	self.weaponmodel = string_null;
 	self.view_ofs = '0 0 -8';
 	self.deadflag = DEAD_DYING;
 	self.solid = SOLID_NOT;
diff --git a/source/subs.qc b/source/subs.qc
index 3ddf62c..f4c400a 100644
--- a/source/subs.qc
+++ b/source/subs.qc
@@ -36,7 +36,7 @@ void() InitTrigger = {
 	setmodel(self, self.model); // set size and link into world
 	self.movetype = MOVETYPE_NONE;
 	self.modelindex = 0;
-	self.model = "";
+	self.model = string_null;
 };
 
 /*
@@ -219,7 +219,7 @@ void() SUB_UseTargets = {
 	//
 	// print the message
 	//
-	if(activator.classname == "player" && self.message != "") {
+	if(activator.classname == "player" && self.message != string_null) {
 		centerprint(activator, self.message);
 		if(!self.noise) {
 			sound(activator, CHAN_VOICE, "misc/talk.wav", 1, ATTN_NORM);
diff --git a/source/triggers.qc b/source/triggers.qc
index ff82c37..8b72373 100644
--- a/source/triggers.qc
+++ b/source/triggers.qc
@@ -384,7 +384,7 @@ void() info_teleport_destination = {
 	// this does nothing, just serves as a target spot
 	self.mangle = self.angles;
 	self.angles = VEC_ORIGIN;
-	self.model = "";
+	self.model = string_null;
 	self.origin = self.origin + '0 0 27';
 	if(!self.targetname) {
 		objerror("no targetname");
@@ -463,11 +463,11 @@ void() trigger_onlyregistered_touch = {
 
 	self.attack_finished = time + 2;
 	if(cvar("registered")) {
-		self.message = "";
+		self.message = string_null;
 		SUB_UseTargets();
 		remove(self);
 	} else {
-		if(self.message != "") {
+		if(self.message != string_null) {
 			centerprint(other, self.message);
 			sound(other, CHAN_BODY, "misc/talk.wav", 1, ATTN_NORM);
 		}
diff --git a/source/weapons.qc b/source/weapons.qc
index b985180..80ef174 100644
--- a/source/weapons.qc
+++ b/source/weapons.qc
@@ -731,7 +731,7 @@ void() W_SetCurrentAmmo = {
 			break;
 		default:
 			self.currentammo = 0;
-			self.weaponmodel = "";
+			self.weaponmodel = string_null;
 			self.weaponframe = 0;
 			break;
 	}
diff --git a/source/world.qc b/source/world.qc
index 5d9036b..cdd6d66 100644
--- a/source/world.qc
+++ b/source/world.qc
@@ -186,9 +186,9 @@ void() StartFrame = {
 	temp1flag  = cvar("temp1");
 	framecount = framecount + 1;
 
-	sf_cheats    = temp1flag & SF_CHEATS;
+	sf_cheats    = (temp1flag & SF_CHEATS) != 0;
 	sf_lives     = bit_shift_right(temp1flag & SF_LIVES_MSK, SF_LIVES_BEG);
-	sf_dist_ammo = temp1flag & SF_DIST_AMMO;
+	sf_dist_ammo = (temp1flag & SF_DIST_AMMO) != 0;
 };
 
 /*