diff --git a/quake/bringback.qc b/quake/bringback.qc
index ff5fcbb..65771b6 100644
--- a/quake/bringback.qc
+++ b/quake/bringback.qc
@@ -31,11 +31,11 @@
 				break;
 			case "monster_fish":
 				setsize (self, '-16 -16 -24', '16 16 24');
-				self.flags = self.flags + FL_SWIM;
+				self.flags |= FL_SWIM;
 				break;
 			case "monster_wizard":
 				setsize (self, '-16 -16 -24', '16 16 40');
-				self.flags = self.flags + FL_FLY;
+				self.flags |= FL_FLY;
 				break;
 			default:
 				// about 3/4 of quakes critters use this size
diff --git a/quake/client.qc b/quake/client.qc
index a24c3fe..d9e27cf 100644
--- a/quake/client.qc
+++ b/quake/client.qc
@@ -548,7 +548,7 @@ void() NextLevel =
 			serverflags |= 4;
 		} else if (!(serverflags & 8)) {
 			mapname = "e4m1";
-			serverflags -= 7; //FIXME should this be &= ~7?
+			serverflags &= ~7;
 		}
 
 		o = spawn();
diff --git a/quake/demon.qc b/quake/demon.qc
index fa7238e..b16dc8d 100644
--- a/quake/demon.qc
+++ b/quake/demon.qc
@@ -82,7 +82,7 @@ void()	demon1_jump4	=[	$leap4,		demon1_jump5	]
 	self.origin_z = self.origin_z + 1;
 	self.velocity = v_forward * 600 + '0 0 250';
 	if (self.flags & FL_ONGROUND)
-		self.flags = self.flags - FL_ONGROUND;
+		self.flags &= ~FL_ONGROUND;
 };
 void()	demon1_jump5	=[	$leap5,		demon1_jump6	] {};
 void()	demon1_jump6	=[	$leap6,		demon1_jump7	] {};
@@ -355,7 +355,7 @@ void()	Demon_JumpTouch =
 //			self.velocity_x = (random() - 0.5) * 600;
 //			self.velocity_y = (random() - 0.5) * 600;
 //			self.velocity_z = 200;
-//			self.flags = self.flags - FL_ONGROUND;
+//			self.flags &= ~FL_ONGROUND;
 		}
 		return;	// not on ground yet
 	}
diff --git a/quake/dog.qc b/quake/dog.qc
index d9b4f1b..1291b00 100644
--- a/quake/dog.qc
+++ b/quake/dog.qc
@@ -90,7 +90,7 @@ void()	Dog_JumpTouch =
 //			self.velocity_x = (random() - 0.5) * 600;
 //			self.velocity_y = (random() - 0.5) * 600;
 //			self.velocity_z = 200;
-//			self.flags = self.flags - FL_ONGROUND;
+//			self.flags &= ~FL_ONGROUND;
 		}
 		return;	// not on ground yet
 	}
@@ -160,7 +160,7 @@ void() dog_leap2	=[	$leap2,		dog_leap3	]
 	self.origin_z = self.origin_z + 1;
 	self.velocity = v_forward * 300 + '0 0 200';
 	if (self.flags & FL_ONGROUND)
-		self.flags = self.flags - FL_ONGROUND;
+		self.flags &= ~FL_ONGROUND;
 };
 
 void() dog_leap3	=[	$leap3,		dog_leap4	] {};
diff --git a/quake/misc.qc b/quake/misc.qc
index dabd82d..4c94aac 100644
--- a/quake/misc.qc
+++ b/quake/misc.qc
@@ -23,12 +23,12 @@ void() light_use =
 	if (self.spawnflags & START_OFF)
 	{
 		lightstyle(self.style, "m");
-		self.spawnflags = self.spawnflags - START_OFF;
+		self.spawnflags &= ~START_OFF;
 	}
 	else
 	{
 		lightstyle(self.style, "a");
-		self.spawnflags = self.spawnflags + START_OFF;
+		self.spawnflags |= START_OFF;
 	}
 };
 
diff --git a/quake/monsters.qc b/quake/monsters.qc
index f89d2f8..09612e7 100644
--- a/quake/monsters.qc
+++ b/quake/monsters.qc
@@ -50,9 +50,9 @@ void() monster_death_use =
 {
 // fall to ground
 	if (self.flags & FL_FLY)
-		self.flags = self.flags - FL_FLY;
+		self.flags &= ~FL_FLY;
 	if (self.flags & FL_SWIM)
-		self.flags = self.flags - FL_SWIM;
+		self.flags &= ~FL_SWIM;
 
 	if (!self.target)
 		return;
diff --git a/quake/tarbaby.qc b/quake/tarbaby.qc
index 71747f0..b185851 100644
--- a/quake/tarbaby.qc
+++ b/quake/tarbaby.qc
@@ -111,7 +111,7 @@ void()	Tar_JumpTouch =
 //			self.velocity_x = (random () - 0.5) * 600;
 //			self.velocity_y = (random () - 0.5) * 600;
 //			self.velocity_z = 200;
-//			self.flags = self.flags - FL_ONGROUND;
+//			self.flags &= ~FL_ONGROUND;
 		}
 		return;	// not on ground yet
 	}