diff --git a/src/g_strife/a_spectral.cpp b/src/g_strife/a_spectral.cpp
index 6e2e6488e1..6f80fe42c5 100644
--- a/src/g_strife/a_spectral.cpp
+++ b/src/g_strife/a_spectral.cpp
@@ -95,7 +95,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_Tracer2)
 		return;
 
 	// change angle
-	exact = R_PointToAngle2 (self->x, self->y, dest->x, dest->y);
+	exact = self->AngleTo(dest);
 
 	if (exact != self->angle)
 	{
@@ -120,8 +120,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_Tracer2)
 	if (!(self->flags3 & (MF3_FLOORHUGGER|MF3_CEILINGHUGGER)))
 	{
 		// change slope
-		dist = P_AproxDistance (dest->x - self->x, dest->y - self->y);
-		dist /= self->Speed;
+		dist = self->AproxDistance (dest) / self->Speed;
 
 		if (dist < 1)
 		{
diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index 87641efe28..6f136d98b7 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -1954,11 +1954,14 @@ bool FBehavior::Init(int lumpnum, FileReader * fr, int len)
 			int arraynum = MapVarStore[LittleLong(chunk[2])];
 			if ((unsigned)arraynum < (unsigned)NumArrays)
 			{
-				int initsize = MIN<int> (ArrayStore[arraynum].ArraySize, (LittleLong(chunk[1])-4)/4);
+				// Use unsigned iterator here to avoid issue with GCC 4.9/5.x
+				// optimizer. Might be some undefined behavior in this code,
+				// but I don't know what it is.
+				unsigned int initsize = MIN<unsigned int> (ArrayStore[arraynum].ArraySize, (LittleLong(chunk[1])-4)/4);
 				SDWORD *elems = ArrayStore[arraynum].Elements;
-				for (i = 0; i < initsize; ++i)
+				for (unsigned int j = 0; j < initsize; ++j)
 				{
-					elems[i] = LittleLong(chunk[3+i]);
+					elems[j] = LittleLong(chunk[3+j]);
 				}
 			}
 			chunk = (DWORD *)NextChunk((BYTE *)chunk);
diff --git a/src/p_conversation.cpp b/src/p_conversation.cpp
index db5fd400c4..a74b9bd18e 100644
--- a/src/p_conversation.cpp
+++ b/src/p_conversation.cpp
@@ -1345,12 +1345,14 @@ static void HandleReply(player_t *player, bool isconsole, int nodenum, int reply
 	if (reply->NextNode != 0)
 	{
 		int rootnode = npc->ConversationRoot;
-		if (reply->NextNode < 0)
+		unsigned next = (unsigned)(rootnode + (reply->NextNode < 0 ? -1 : 1) * reply->NextNode - 1);
+
+		if (next < StrifeDialogues.Size())
 		{
-			unsigned next = (unsigned)(rootnode - reply->NextNode - 1);
-			if (gameaction != ga_slideshow && next < StrifeDialogues.Size())
+			npc->Conversation = StrifeDialogues[next];
+
+			if (gameaction != ga_slideshow)
 			{
-				npc->Conversation = StrifeDialogues[next];
 				P_StartConversation (npc, player->mo, player->ConversationFaceTalker, false);
 				return;
 			}
@@ -1359,10 +1361,6 @@ static void HandleReply(player_t *player, bool isconsole, int nodenum, int reply
 				S_StopSound (npc, CHAN_VOICE);
 			}
 		}
-		else
-		{
-			npc->Conversation = StrifeDialogues[rootnode + reply->NextNode - 1];
-		}
 	}
 
 	npc->angle = player->ConversationNPCAngle;
diff --git a/src/p_local.h b/src/p_local.h
index e8cc5fde03..8597229121 100644
--- a/src/p_local.h
+++ b/src/p_local.h
@@ -380,7 +380,6 @@ class FPathTraverse
 	divline_t trace;
 	unsigned int intercept_index;
 	unsigned int intercept_count;
-	fixed_t maxfrac;
 	unsigned int count;
 
 	void AddLineIntercepts(int bx, int by);
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 3381f763f3..4132e90b58 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -545,7 +545,7 @@ inline fixed_t secfriction(const sector_t *sec, int plane = sector_t::floor)
 
 inline fixed_t secmovefac(const sector_t *sec, int plane = sector_t::floor)
 {
-	if (sec->Flags & SECF_FRICTION) return sec->friction;
+	if (sec->Flags & SECF_FRICTION) return sec->movefactor;
 	fixed_t movefactor = Terrains[sec->GetTerrain(plane)].MoveFactor;
 	return movefactor != 0 ? movefactor : ORIG_FRICTION_FACTOR;
 }
@@ -4297,6 +4297,14 @@ void P_RailAttack(AActor *source, int damage, int offset_xy, fixed_t offset_z, i
 			SpawnShootDecal(source, trace);
 
 	}
+	if (trace.HitType == TRACE_HitFloor || trace.HitType == TRACE_HitCeiling)
+	{
+		AActor* puff = NULL;
+		if (puffclass != NULL && puffDefaults->flags3 & MF3_ALWAYSPUFF)
+		{
+			puff = P_SpawnPuff(source, puffclass, trace.X, trace.Y, trace.Z, (source->angle + angleoffset) - ANG90, 1, 0);
+		}
+	}
 	if (thepuff != NULL)
 	{
 		if (trace.HitType == TRACE_HitFloor &&
diff --git a/src/p_maputl.cpp b/src/p_maputl.cpp
index 1d806d0449..85e9183c57 100644
--- a/src/p_maputl.cpp
+++ b/src/p_maputl.cpp
@@ -985,7 +985,7 @@ void FPathTraverse::AddLineIntercepts(int bx, int by)
 		P_MakeDivline (ld, &dl);
 		frac = P_InterceptVector (&trace, &dl);
 
-		if (frac < 0) continue;	// behind source
+		if (frac < 0 || frac > 1) continue;	// behind source or beyond end point
 			
 		intercept_t newintercept;
 
@@ -1170,7 +1170,7 @@ intercept_t *FPathTraverse::Next()
 		}
 	}
 	
-	if (dist > maxfrac || in == NULL) return NULL;	// checked everything in range			
+	if (dist > FRACUNIT || in == NULL) return NULL;	// checked everything in range			
 	in->done = true;
 	return in;
 }
@@ -1388,7 +1388,6 @@ FPathTraverse::FPathTraverse (fixed_t x1, fixed_t y1, fixed_t x2, fixed_t y2, in
 			break;
 		}
 	}
-	maxfrac = FRACUNIT;
 }
 
 FPathTraverse::~FPathTraverse()
diff --git a/wadsrc/static/compatibility.txt b/wadsrc/static/compatibility.txt
index e592a25e7f..478dffdc7f 100644
--- a/wadsrc/static/compatibility.txt
+++ b/wadsrc/static/compatibility.txt
@@ -403,6 +403,7 @@ D0139194F7817BF06F3988DFC47DB38D // Whispers of Satan map29
 }
 
 D7F6E9F08C39A17026349A04F8C0B0BE // Return to Hadron, e1m9
+19D03FFC875589E21EDBB7AB74EF4AEF // Return to Hadron, e1m9, 2016.01.03 update
 {
 	pointonline
 }