diff --git a/SpaceCadetPinball/TBall.cpp b/SpaceCadetPinball/TBall.cpp
index 25dd48f..b086594 100644
--- a/SpaceCadetPinball/TBall.cpp
+++ b/SpaceCadetPinball/TBall.cpp
@@ -40,7 +40,7 @@ TBall::TBall(TPinballTable* table) : TPinballComponent(table, -1, false)
 
 	Offset = *loader::query_float_attribute(groupIndex, 0, 500);
 	auto visualCount = loader::query_visual_states(groupIndex);
-	auto index = 0;
+	int index = 0;
 	if (visualCount > 0)
 	{
 		auto visualZPtr = VisualZArray;
diff --git a/SpaceCadetPinball/TFlipper.cpp b/SpaceCadetPinball/TFlipper.cpp
index 94999e5..a227c92 100644
--- a/SpaceCadetPinball/TFlipper.cpp
+++ b/SpaceCadetPinball/TFlipper.cpp
@@ -65,7 +65,7 @@ TFlipper::~TFlipper()
 
 int TFlipper::Message(int code, float value)
 {
-	if (code == 1 || code == 2 || code > 1008 && code <= 1011 || code == 1022)
+	if (code == 1 || code == 2 || (code > 1008 && code <= 1011) || code == 1022)
 	{
 		float timerTime;
 		int command = code;
diff --git a/SpaceCadetPinball/TFlipperEdge.cpp b/SpaceCadetPinball/TFlipperEdge.cpp
index 151dc50..3d3821d 100644
--- a/SpaceCadetPinball/TFlipperEdge.cpp
+++ b/SpaceCadetPinball/TFlipperEdge.cpp
@@ -109,7 +109,6 @@ float TFlipperEdge::FindCollisionDistance(ray_type* ray)
 	{
 		if (FlipperFlag == 0)
 		{
-			EdgeCollisionFlag = 0;
 			CollisionFlag1 = 0;
 			CollisionFlag2 = 0;
 			set_control_points(ogRay->TimeNow);
diff --git a/SpaceCadetPinball/TLightGroup.cpp b/SpaceCadetPinball/TLightGroup.cpp
index 2cc1dee..616a906 100644
--- a/SpaceCadetPinball/TLightGroup.cpp
+++ b/SpaceCadetPinball/TLightGroup.cpp
@@ -432,7 +432,7 @@ int TLightGroup::next_light_up()
 {
 	for (auto index = 0u; index < List.size(); ++index)
 	{
-		if (!List.at(index)->BmpIndex1)
+		if (!List[index]->BmpIndex1)
 			return static_cast<int>(index);
 	}
 	return -1;
diff --git a/SpaceCadetPinball/TPinballTable.cpp b/SpaceCadetPinball/TPinballTable.cpp
index 62148f7..810e9c2 100644
--- a/SpaceCadetPinball/TPinballTable.cpp
+++ b/SpaceCadetPinball/TPinballTable.cpp
@@ -368,7 +368,7 @@ int TPinballTable::Message(int code, float value)
 		LightGroup->Message(34, 0.0);
 		LightGroup->Message(20, 0.0);
 		Plunger->Message(1016, 0.0);
-		if (Demo->ActiveFlag)
+		if (Demo && Demo->ActiveFlag)
 			rc_text = pinball::get_rc_string(30, 0);
 		else
 			rc_text = pinball::get_rc_string(26, 0);
diff --git a/SpaceCadetPinball/TPlunger.cpp b/SpaceCadetPinball/TPlunger.cpp
index eb289a3..db9a1ca 100644
--- a/SpaceCadetPinball/TPlunger.cpp
+++ b/SpaceCadetPinball/TPlunger.cpp
@@ -37,7 +37,7 @@ void TPlunger::Collision(TBall* ball, vector_type* nextPosition, vector_type* di
 {
 	if (PinballTable->TiltLockFlag)
 		Message(1017, 0.0);
-	coef = RandFloat() * Boost * 0.1f + Boost;
+	coef = RandFloat() * Boost * 0.1f + Boost; // it is intended that the passed in coef is never used!
 	maths::basic_collision(ball, nextPosition, direction, Elasticity, Smoothness, Threshold, coef);
 }
 
@@ -94,7 +94,7 @@ int TPlunger::Message(int code, float value)
 			if (PullbackTimer_)
 				timer::kill(PullbackTimer_);
 			PullbackTimer_ = 0;
-			if (code == 1005)
+			if (code == 1005) // intended that this can never be reached (same as original)
 				loader::play_sound(SoundIndexP2);
 			auto bmp = ListBitmap->at(0);
 			auto zMap = ListZMap->at(0);
diff --git a/SpaceCadetPinball/TTripwire.cpp b/SpaceCadetPinball/TTripwire.cpp
index 46bdacc..bc34094 100644
--- a/SpaceCadetPinball/TTripwire.cpp
+++ b/SpaceCadetPinball/TTripwire.cpp
@@ -6,7 +6,7 @@
 #include "TBall.h"
 #include "TPinballTable.h"
 
-TTripwire::TTripwire(TPinballTable* table, int groupIndex) : TRollover(table, groupIndex, 1)
+TTripwire::TTripwire(TPinballTable* table, int groupIndex) : TRollover(table, groupIndex, true)
 {
 }
 
diff --git a/SpaceCadetPinball/control.cpp b/SpaceCadetPinball/control.cpp
index 56d8a3b..dc41ae2 100644
--- a/SpaceCadetPinball/control.cpp
+++ b/SpaceCadetPinball/control.cpp
@@ -3923,9 +3923,7 @@ void control::SelectMissionController(int code, TPinballComponent* caller)
 			if (light_on(&control_lite319_tag))
 				control_lite319_tag.Component->Message(20, 0.0);
 			if (!light_on(&control_lite317_tag))
-			{
 				control_lite317_tag.Component->Message(7, 0.0);
-			}
 		}
 		else
 		{
@@ -4158,6 +4156,7 @@ void control::TimeWarpPartTwoController(int code, TPinballComponent* caller)
 	control_lite317_tag.Component->Message(20, 0.0);
 	control_lite198_tag.Component->MessageField = 1;
 	MissionControl(66, nullptr);
+	// SpecialAddScore sets the score dirty flag. So next tick it will be redrawn.
 }
 
 void control::UnselectMissionController(int code, TPinballComponent* caller)
diff --git a/SpaceCadetPinball/maths.cpp b/SpaceCadetPinball/maths.cpp
index 7df44a4..bb41669 100644
--- a/SpaceCadetPinball/maths.cpp
+++ b/SpaceCadetPinball/maths.cpp
@@ -299,7 +299,7 @@ float maths::basic_collision(TBall* ball, vector_type* nextPosition, vector_type
 	return projSpeed;
 }
 
-float maths::Distance_Squared(vector_type vec1, vector_type vec2)
+float maths::Distance_Squared(vector_type& vec1, vector_type& vec2)
 {
 	return (vec1.Y - vec2.Y) * (vec1.Y - vec2.Y) + (vec1.X - vec2.X) * (vec1.X - vec2.X);
 }
diff --git a/SpaceCadetPinball/maths.h b/SpaceCadetPinball/maths.h
index a975463..3e0d767 100644
--- a/SpaceCadetPinball/maths.h
+++ b/SpaceCadetPinball/maths.h
@@ -87,7 +87,7 @@ public:
 	static float basic_collision(TBall* ball, vector_type* nextPosition, vector_type* direction, float elasticity,
 	                             float smoothness,
 	                             float threshold, float boost);
-	static float Distance_Squared(vector_type vec1, vector_type vec2);
+	static float Distance_Squared(vector_type& vec1, vector_type& vec2);
 	static float DotProduct(vector_type* vec1, vector_type* vec2);
 	static void vswap(vector_type* vec1, vector_type* vec2);
 	static float Distance(vector_type* vec1, vector_type* vec2);
diff --git a/SpaceCadetPinball/pb.cpp b/SpaceCadetPinball/pb.cpp
index 95f45e5..4087d93 100644
--- a/SpaceCadetPinball/pb.cpp
+++ b/SpaceCadetPinball/pb.cpp
@@ -29,8 +29,8 @@
 
 TPinballTable* pb::MainTable = nullptr;
 DatFile* pb::record_table = nullptr;
-int pb::time_ticks = 0, pb::demo_mode = 0, pb::game_mode = 2, pb::mode_countdown_;
-float pb::time_now = 0, pb::time_next = 0, pb::ball_speed_limit, pb::time_ticks_remainder = 0;
+int pb::time_ticks = 0, pb::demo_mode = 0, pb::game_mode = 2;
+float pb::mode_countdown_, pb::time_now = 0, pb::time_next = 0, pb::ball_speed_limit, pb::time_ticks_remainder = 0;
 high_score_struct pb::highscore_table[5];
 bool pb::FullTiltMode = false, pb::cheat_mode = false;
 
@@ -169,7 +169,7 @@ void pb::mode_change(int mode)
 	case 4:
 		winmain::LaunchBallEnabled = false;
 		winmain::HighScoresEnabled = false;
-		mode_countdown_ = 5000;
+		mode_countdown_ = 5000.f;
 		break;
 	}
 	game_mode = mode;
@@ -317,7 +317,7 @@ void pb::window_size(int* width, int* height)
 
 void pb::pause_continue()
 {
-	winmain::single_step = winmain::single_step == 0;
+	winmain::single_step = (winmain::single_step == 0) ? 1 : 0;
 	pinball::InfoTextBox->Clear();
 	pinball::MissTextBox->Clear();
 	if (winmain::single_step)
@@ -399,7 +399,7 @@ void pb::InputDown(GameInput input)
 
 	if (game_mode != 1)
 	{
-		mode_countdown(-1);
+		mode_countdown(-1.f);
 		return;
 	}
 
@@ -485,7 +485,7 @@ void pb::InputDown(GameInput input)
 	}
 }
 
-int pb::mode_countdown(int time)
+int pb::mode_countdown(float time)
 {
 	if (!game_mode || game_mode <= 0)
 		return 1;
@@ -494,13 +494,13 @@ int pb::mode_countdown(int time)
 		if (game_mode == 3)
 		{
 			mode_countdown_ -= time;
-			if (mode_countdown_ < 0 || time < 0)
+			if (mode_countdown_ < 0.f || time < 0.f)
 				mode_change(4);
 		}
 		else if (game_mode == 4)
 		{
 			mode_countdown_ -= time;
-			if (mode_countdown_ < 0 || time < 0)
+			if (mode_countdown_ < 0.f || time < 0.f)
 				mode_change(1);
 		}
 		return 1;
@@ -532,7 +532,7 @@ void pb::end_game()
 
 	for (auto i = 0; i < playerCount; ++i)
 	{
-		for (auto j = i; j < playerCount; ++j)
+		for (auto j = i+1; j < playerCount; ++j)
 		{
 			if (scores[j] > scores[i])
 			{
diff --git a/SpaceCadetPinball/pb.h b/SpaceCadetPinball/pb.h
index 0139db2..e787dc4 100644
--- a/SpaceCadetPinball/pb.h
+++ b/SpaceCadetPinball/pb.h
@@ -57,7 +57,7 @@ public:
 	static void loose_focus();
 	static void InputUp(GameInput input);
 	static void InputDown(GameInput input);
-	static int mode_countdown(int time);
+	static int mode_countdown(float time);
 	static void launch_ball();
 	static void end_game();
 	static void high_scores();
@@ -66,7 +66,8 @@ public:
 	static float collide(float timeNow, float timeDelta, TBall* ball);
 	static void PushCheat(const std::string& cheat);
 private:
-	static int demo_mode, mode_countdown_;
+	static int demo_mode;
+	static float mode_countdown_;
 
 	static bool AnyBindingMatchesInput(GameInput (&options)[3], GameInput key);
 };
diff --git a/SpaceCadetPinball/render.cpp b/SpaceCadetPinball/render.cpp
index 30d6b35..40d0bb6 100644
--- a/SpaceCadetPinball/render.cpp
+++ b/SpaceCadetPinball/render.cpp
@@ -420,7 +420,7 @@ void render::build_occlude_list()
 				}
 			}
 
-			if (!mainSprite->UnknownFlag && mainSprite->Bmp && spriteArr->size() < 2)
+			if (mainSprite->Bmp && spriteArr->size() < 2)
 				spriteArr->clear();
 			if (!spriteArr->empty())
 			{
diff --git a/SpaceCadetPinball/winmain.cpp b/SpaceCadetPinball/winmain.cpp
index cef4dbe..f8926bc 100644
--- a/SpaceCadetPinball/winmain.cpp
+++ b/SpaceCadetPinball/winmain.cpp
@@ -180,7 +180,7 @@ int winmain::WinMain(LPCSTR lpCmdLine)
 			if (!gfr_display)
 			{
 				auto plt = static_cast<ColorRgba*>(malloc(1024u));
-				auto pltPtr = &plt[10];
+				auto pltPtr = &plt[10]; // first 10 entries are system colors hardcoded in display_palette()
 				for (int i1 = 0, i2 = 0; i1 < 256 - 10; ++i1, i2 += 8)
 				{
 					unsigned char blue = i2, redGreen = i2;
@@ -215,8 +215,8 @@ int winmain::WinMain(LPCSTR lpCmdLine)
 				int x, y, w, h;
 				SDL_GetMouseState(&x, &y);
 				SDL_GetWindowSize(window, &w, &h);
-				float dx = (last_mouse_x - x) / static_cast<float>(w);
-				float dy = (y - last_mouse_y) / static_cast<float>(h);
+				float dx = static_cast<float>(last_mouse_x - x) / static_cast<float>(w);
+				float dy = static_cast<float>(y - last_mouse_y) / static_cast<float>(h);
 				pb::ballset(dx, dy);
 
 				SDL_WarpMouseInWindow(window, last_mouse_x, last_mouse_y);
@@ -655,7 +655,7 @@ int winmain::event_handler(const SDL_Event* event)
 			pb::frame(10);
 			break;
 		case SDLK_F10:
-			single_step = single_step == 0;
+			single_step = (single_step == 0) ? 1 : 0;
 			if (single_step == 0)
 				no_time_loss = 1;
 			break;