diff --git a/src/alien.cpp b/src/alien.cpp
index 57a7d93..8698e98 100644
--- a/src/alien.cpp
+++ b/src/alien.cpp
@@ -1642,7 +1642,7 @@ void alien_move(object *alien)
 		{
 			if (alien->classDef == CD_ASTEROID)
 			{
-				if (!engine.cheatShield)
+				if ((!engine.cheatShield) && (engine.missionCompleteTimer == 0))
 					player.shield -= alien->shield;
 				alien->shield = 0;
 				audio_playSound(SFX_EXPLOSION, alien->x);
@@ -1652,7 +1652,7 @@ void alien_move(object *alien)
 
 			if (alien->classDef == CD_ASTEROID2)
 			{
-				if (!engine.cheatShield)
+				if ((!engine.cheatShield) && (engine.missionCompleteTimer == 0))
 					player.shield -= alien->shield;
 				alien->shield = 0;
 				audio_playSound(SFX_EXPLOSION, alien->x);
@@ -1662,7 +1662,7 @@ void alien_move(object *alien)
 
 			if (alien->classDef == CD_BARRIER)
 			{
-				if (!engine.cheatShield)
+				if ((!engine.cheatShield) && (engine.missionCompleteTimer == 0))
 					player.shield--;
 				player.hit = 5;
 				audio_playSound(SFX_HIT, player.x);
diff --git a/src/game.cpp b/src/game.cpp
index 6384ec5..4d3f00b 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -678,7 +678,7 @@ static void game_doBullets()
 				{
 					old_shield = player.shield;
 
-					if ((!engine.cheatShield) || (engine.missionCompleteTimer != 0))
+					if ((!engine.cheatShield) && (engine.missionCompleteTimer == 0))
 					{
 						if ((player.shield > engine.lowShield) &&
 								(player.shield - bullet->damage <= engine.lowShield))
diff --git a/src/ship.cpp b/src/ship.cpp
index a43b240..3470979 100644
--- a/src/ship.cpp
+++ b/src/ship.cpp
@@ -164,8 +164,8 @@ void ship_fireRay(object *ship)
 		if (player.shield > 0)
 		{
 			if (game_collision(player.x, player.y, player.image[0]->w,
-					player.image[0]->h, ray.x, ray.y, ray.w, ray.h) &&
-				(!engine.cheatShield))
+						player.image[0]->h, ray.x, ray.y, ray.w, ray.h) &&
+					(!engine.cheatShield) && (engine.missionCompleteTimer == 0))
 			{
 				if (player.shield > engine.lowShield)
 				{