diff --git a/Source/controls/devices/game_controller.cpp b/Source/controls/devices/game_controller.cpp
index 55512d4eb..b1e78d84d 100644
--- a/Source/controls/devices/game_controller.cpp
+++ b/Source/controls/devices/game_controller.cpp
@@ -271,7 +271,10 @@ GamepadLayout GameController::getLayout(const SDL_Event &event)
 	case SDL_CONTROLLER_TYPE_VIRTUAL:
 #endif
 	case SDL_CONTROLLER_TYPE_UNKNOWN:
-		return GamepadLayout::Generic;
+#if SDL_VERSION_ATLEAST(2, 30, 0)
+	case SDL_CONTROLLER_TYPE_MAX:
+#endif
+		break;
 	}
 #endif
 	return GamepadLayout::Generic;
diff --git a/Source/cursor.cpp b/Source/cursor.cpp
index c2e5dd0e6..33c259002 100644
--- a/Source/cursor.cpp
+++ b/Source/cursor.cpp
@@ -470,7 +470,7 @@ void CreateHalfSizeItemSprites()
 {
 	if (HalfSizeItemSprites != nullptr)
 		return;
-	const int numInvItems = pCursCels->numSprites() - (static_cast<size_t>(CURSOR_FIRSTITEM) - 1)
+	const uint32_t numInvItems = pCursCels->numSprites() - (static_cast<uint32_t>(CURSOR_FIRSTITEM) - 1)
 	    + (gbIsHellfire ? pCursCels2->numSprites() : 0);
 	HalfSizeItemSprites = new OptionalOwnedClxSpriteList[numInvItems];
 	HalfSizeItemSpritesRed = new OptionalOwnedClxSpriteList[numInvItems];
diff --git a/Source/engine/render/scrollrt.cpp b/Source/engine/render/scrollrt.cpp
index f0dd77a46..aabb04503 100644
--- a/Source/engine/render/scrollrt.cpp
+++ b/Source/engine/render/scrollrt.cpp
@@ -45,6 +45,7 @@
 #include "qol/xpbar.h"
 #include "stores.h"
 #include "towners.h"
+#include "utils/attributes.h"
 #include "utils/bitset2d.hpp"
 #include "utils/display.h"
 #include "utils/endian.hpp"
@@ -758,6 +759,8 @@ void DrawDungeon(const Surface &out, Point tilePosition, Point targetBufferPosit
 				case Direction::SouthEast:
 					tempTargetBufferPosition += { -TILE_WIDTH / 2, -TILE_HEIGHT / 2 };
 					break;
+				default:
+					DVL_UNREACHABLE();
 				}
 				tempTilePosition += Opposite(player->_pdir);
 			} else if (player->_pmode == PM_WALK_SIDEWAYS && player->_pdir == Direction::East) {
@@ -793,6 +796,8 @@ void DrawDungeon(const Surface &out, Point tilePosition, Point targetBufferPosit
 				case Direction::SouthEast:
 					tempTargetBufferPosition += { -TILE_WIDTH / 2, -TILE_HEIGHT / 2 };
 					break;
+				default:
+					DVL_UNREACHABLE();
 				}
 				tempTilePosition += Opposite(monster->direction);
 			} else if (monster->mode == MonsterMode::MoveSideways && monster->direction == Direction::East) {
diff --git a/Source/missiles.cpp b/Source/missiles.cpp
index 713c153c2..8f1d2cf9a 100644
--- a/Source/missiles.cpp
+++ b/Source/missiles.cpp
@@ -691,7 +691,7 @@ bool GuardianTryFireAt(Missile &missile, Point target)
 
 bool GrowWall(int id, Point position, Point target, MissileID type, int spellLevel, int damage)
 {
-	int dp = dPiece[position.x][position.y];
+	[[maybe_unused]] int dp = dPiece[position.x][position.y];
 	assert(dp <= MAXTILES && dp >= 0);
 
 	if (TileHasAny(position, TileProperties::BlockMissile) || !InDungeonBounds(target)) {
@@ -719,7 +719,7 @@ void SpawnLightning(Missile &missile, int dam)
 	MoveMissile(
 	    missile, [&](Point tile) {
 		    assert(InDungeonBounds(tile));
-		    int pn = dPiece[tile.x][tile.y];
+		    [[maybe_unused]] int pn = dPiece[tile.x][tile.y];
 		    assert(pn >= 0 && pn <= MAXTILES);
 
 		    if (!missile.IsTrap() || tile != missile.position.start) {
@@ -3805,7 +3805,7 @@ void ProcessFlameWaveControl(Missile &missile)
 	Direction dira = Left(Left(sd));
 	Direction dirb = Right(Right(sd));
 	Point na = src + sd;
-	int pn = dPiece[na.x][na.y];
+	[[maybe_unused]] int pn = dPiece[na.x][na.y];
 	assert(pn >= 0 && pn <= MAXTILES);
 	if (!TileHasAny(na, TileProperties::BlockMissile)) {
 		Direction pdir = Players[id]._pdir;
diff --git a/Source/monster.cpp b/Source/monster.cpp
index bc34261ae..c2bde27e1 100644
--- a/Source/monster.cpp
+++ b/Source/monster.cpp
@@ -41,6 +41,7 @@
 #include "spelldat.h"
 #include "storm/storm_net.hpp"
 #include "towners.h"
+#include "utils/attributes.h"
 #include "utils/cl2_to_clx.hpp"
 #include "utils/file_name_generator.hpp"
 #include "utils/language.h"
@@ -734,6 +735,9 @@ void WalkInDirection(Monster &monster, Direction endDir)
 	case Direction::SouthEast:
 		mode = MonsterMode::MoveSouthwards;
 		break;
+	case Direction::NoDirection:
+		DVL_UNREACHABLE();
+		break;
 	}
 	monster.mode = mode;
 	monster.position.old = monster.position.tile;
diff --git a/Source/utils/attributes.h b/Source/utils/attributes.h
index 309c8bc3f..7d2beb962 100644
--- a/Source/utils/attributes.h
+++ b/Source/utils/attributes.h
@@ -88,3 +88,11 @@
 #ifndef DVL_ASSUME
 #define DVL_ASSUME(...)
 #endif
+
+#if defined(__clang__) || defined(__GNUC__)
+#define DVL_UNREACHABLE() __builtin_unreachable()
+#elif defined(_MSC_VER)
+#define DVL_UNREACHABLE() __assume(false)
+#else
+#define DVL_UNREACHABLE()
+#endif