diff --git a/sc2/src/sc2code/comm/spathi/spathic.c b/sc2/src/sc2code/comm/spathi/spathic.c
index a8ad831ea..9199dcd7b 100644
--- a/sc2/src/sc2code/comm/spathi/spathic.c
+++ b/sc2/src/sc2code/comm/spathi/spathic.c
@@ -116,7 +116,7 @@ static LOCDATA spathi_desc =
 		0, /* AnimFlags */
 		0, 0, /* FrameRate */
 		0, 0, /* RestartRate */
-			0, /* BlockMask */
+		0, /* BlockMask */
 	},
 #ifdef NEVER
 	{ /* AlienTalkDesc */
diff --git a/sc2/src/sc2code/dummy.c b/sc2/src/sc2code/dummy.c
index 12f55ba0c..6abaa8577 100644
--- a/sc2/src/sc2code/dummy.c
+++ b/sc2/src/sc2code/dummy.c
@@ -368,4 +368,5 @@ void *
 ReleaseCodeRes (void *CodeRef)
 {
 	return CodeRef;
-}
\ No newline at end of file
+}
+
diff --git a/sc2/src/sc2code/globdata.h b/sc2/src/sc2code/globdata.h
index a54184227..b1b69a054 100644
--- a/sc2/src/sc2code/globdata.h
+++ b/sc2/src/sc2code/globdata.h
@@ -39,6 +39,10 @@
 		// Mask of all animation types.
 
 #define WAIT_TALKING (1 << 3)
+		// This is set in AlienTalkDesc when the ambient animations should
+		// stop at the end of the current animation cycle.
+		// In AlienAmbientArray, this is set for those ambient animations
+		// which can not be active while the talking animation is active.
 #define PAUSE_TALKING (1 << 4)
 #define TALK_INTRO (1 << 5)
 #define TALK_DONE (1 << 6)
@@ -64,6 +68,8 @@ typedef struct
 	COUNT RandomRestartRate;
 
 	DWORD BlockMask;
+			// Bit mask of the indices of all animations that can not
+			// be active at the same time as this animation.
 } ANIMATION_DESC;
 
 #define MAX_ANIMATIONS 20
diff --git a/sc2/src/sc2code/grpinfo.c b/sc2/src/sc2code/grpinfo.c
index 7c067a9ef..0b593dc91 100644
--- a/sc2/src/sc2code/grpinfo.c
+++ b/sc2/src/sc2code/grpinfo.c
@@ -285,7 +285,14 @@ BuildGroups (void)
 	EncounterPercent[SLYLANDRO_SHIP] *= GET_GAME_STATE (SLYLANDRO_MULTIPLIER);
 	Index = GET_GAME_STATE (UTWIG_SUPOX_MISSION);
 	if (Index > 1 && Index < 5)
-		HomeWorld[UTWIG_SHIP] = HomeWorld[SUPOX_SHIP] = 0;
+	{
+		// XXX: The BuildGroups function is only called when there is no
+		// existing battle group for the system (right?). Is it even
+		// possible to start the Utwig/Supox mission without visiting their
+		// home systems?
+		HomeWorld[UTWIG_SHIP] = 0;
+		HomeWorld[SUPOX_SHIP] = 0;
+	}
 
 	BestPercent = 0;
 	universe = CurStarDescPtr->star_pt;
diff --git a/sc2/src/sc2code/hyper.c b/sc2/src/sc2code/hyper.c
index d5f63adae..4e06083cc 100644
--- a/sc2/src/sc2code/hyper.c
+++ b/sc2/src/sc2code/hyper.c
@@ -457,8 +457,8 @@ unhyper_transition (ELEMENT *ElementPtr)
 				{
 					POINT pt;
 
-					GLOBAL (autopilot.x) =
-							GLOBAL (autopilot.y) = ~0;
+					GLOBAL (autopilot.x) = ~0;
+					GLOBAL (autopilot.y) = ~0;
 
 					ElementToUniverse (ElementPtr, &pt);
 					CurStarDescPtr = FindStar (NULL, &pt, 5, 5);
@@ -507,15 +507,13 @@ unhyper_transition (ELEMENT *ElementPtr)
 				 */
 				GLOBAL (ShipStamp.frame) = 0;
 				SET_GAME_STATE (USED_BROADCASTER, 0);
-				GLOBAL (autopilot.x) =
-						GLOBAL (autopilot.y) = ~0;
+				GLOBAL (autopilot.x) = ~0;
+				GLOBAL (autopilot.y) = ~0;
 				if (GET_GAME_STATE (ARILOU_SPACE_SIDE) <= 1)
 				{
 					// From HyperSpace to QuasiSpace.
-					GLOBAL_SIS (log_x) =
-							UNIVERSE_TO_LOGX (QUASI_SPACE_X);
-					GLOBAL_SIS (log_y) =
-							UNIVERSE_TO_LOGY (QUASI_SPACE_Y);
+					GLOBAL_SIS (log_x) = UNIVERSE_TO_LOGX (QUASI_SPACE_X);
+					GLOBAL_SIS (log_y) = UNIVERSE_TO_LOGY (QUASI_SPACE_Y);
 					if (GET_GAME_STATE (PORTAL_COUNTER) == 0)
 					{
 						// Periodically appearing portal.
@@ -532,10 +530,8 @@ unhyper_transition (ELEMENT *ElementPtr)
 				{
 					// From QuasiSpace to HyperSpace through the
 					// periodically appearing portal.
-					GLOBAL_SIS (log_x) =
-							UNIVERSE_TO_LOGX (ARILOU_SPACE_X);
-					GLOBAL_SIS (log_y) =
-							UNIVERSE_TO_LOGY (ARILOU_SPACE_Y);
+					GLOBAL_SIS (log_x) = UNIVERSE_TO_LOGX (ARILOU_SPACE_X);
+					GLOBAL_SIS (log_y) = UNIVERSE_TO_LOGY (ARILOU_SPACE_Y);
 					SET_GAME_STATE (ARILOU_SPACE_SIDE, 0);
 				}
 				break;
diff --git a/sc2/src/sc2code/planets/planets.h b/sc2/src/sc2code/planets/planets.h
index a9e99daa5..43a82abdf 100644
--- a/sc2/src/sc2code/planets/planets.h
+++ b/sc2/src/sc2code/planets/planets.h
@@ -53,18 +53,28 @@ enum
 enum
 {
 	GENERATE_PLANETS = 0,
+			// Layout of planets within a solar system.
 	GENERATE_MOONS,
+			// Layout of moons around a planet.
 	GENERATE_ORBITAL,
+			// Characteristics of words (planets and moons).
 
 	INIT_NPCS,
+			// Ships in the solar system, the first time it is accessed.
 	REINIT_NPCS,
+			// Ships in the solar system, every next time it is accessed.
 	UNINIT_NPCS,
+			// When leaving the solar system.
 
 	GENERATE_MINERAL,
+			// Minerals on the planet surface.
 	GENERATE_ENERGY,
+			// Energy sources on the planet surface.
 	GENERATE_LIFE,
+			// Bio on the planet surface.
 
 	GENERATE_NAME
+			// Name of a planet.
 };
 
 enum
@@ -74,7 +84,7 @@ enum
 	LIGHTNING_DISASTER,
 	LAVASPOT_DISASTER,
 
-		/* additional lander sounds */
+	/* additional lander sounds */
 	LANDER_INJURED,
 	LANDER_SHOOTS,
 	LANDER_HITS,