diff --git a/engines/parallaction/disk.cpp b/engines/parallaction/disk.cpp
index 387499a51aa..9f98e0b7861 100644
--- a/engines/parallaction/disk.cpp
+++ b/engines/parallaction/disk.cpp
@@ -172,7 +172,7 @@ void Disk::loadCnv(const char *filename, Cnv *cnv) {
 
 void Disk::loadTalk(const char *name, Cnv *cnv) {
 
-	char* ext = strstr(name, ".talk");
+	const char *ext = strstr(name, ".talk");
 	if (ext != NULL) {
 		// npc talk
 		loadCnv(name, cnv);
diff --git a/engines/queen/display.cpp b/engines/queen/display.cpp
index 274924d8d9e..2a59d32739e 100644
--- a/engines/queen/display.cpp
+++ b/engines/queen/display.cpp
@@ -845,7 +845,7 @@ void Display::decodePCX(const uint8 *src, uint32 srcSize, uint8 *dst, uint16 dst
 }
 
 void Display::decodeLBM(const uint8 *src, uint32 srcSize, uint8 *dst, uint16 dstPitch, uint16 *w, uint16 *h, uint8 *pal, uint16 palStart, uint16 palEnd, uint8 colorBase) {
-	int planeCount, planePitch;
+	int planeCount = 0, planePitch = 0;
 	const uint8 *srcEnd = src + srcSize;
 	src += 12;
 	while (src < srcEnd) {
diff --git a/engines/scumm/player_nes.cpp b/engines/scumm/player_nes.cpp
index 4836ad5629b..a59a7437a23 100644
--- a/engines/scumm/player_nes.cpp
+++ b/engines/scumm/player_nes.cpp
@@ -176,7 +176,7 @@ void Square::Write(int Reg, byte Val) {
 		break;
 
 	case 4:
-		Enabled = Val;
+		Enabled = (Val != 0);
 		if (!Enabled)
 			Timer = 0;
 		break;
@@ -294,7 +294,7 @@ void Triangle::Write(int Reg, byte Val) {
 		break;
 
 	case 4:
-		Enabled = Val;
+		Enabled = (Val != 0);
 		if (!Enabled)
 			Timer = 0;
 		break;
@@ -391,7 +391,7 @@ void Noise::Write(int Reg, byte Val) {
 		break;
 
 	case 4:
-		Enabled = Val;
+		Enabled = (Val != 0);
 		if (!Enabled)
 			Timer = 0;
 		break;