diff --git a/src/openrct2/windows/dropdown.cpp b/src/openrct2/windows/dropdown.cpp
index 5978c67186..b9d379b93d 100644
--- a/src/openrct2/windows/dropdown.cpp
+++ b/src/openrct2/windows/dropdown.cpp
@@ -64,7 +64,7 @@ sint32 gDropdownDefaultIndex;
 
 bool dropdown_is_checked(sint32 index)
 {
-    if (index < 0 || index >= Util::CountOf(_dropdownItemsDisabled))
+    if (index < 0 || index >= (sint32)Util::CountOf(_dropdownItemsDisabled))
     {
         return false;
     }
@@ -73,7 +73,7 @@ bool dropdown_is_checked(sint32 index)
 
 bool dropdown_is_disabled(sint32 index)
 {
-    if (index < 0 || index >= Util::CountOf(_dropdownItemsDisabled))
+    if (index < 0 || index >= (sint32)Util::CountOf(_dropdownItemsDisabled))
     {
         return true;
     }
@@ -82,7 +82,7 @@ bool dropdown_is_disabled(sint32 index)
 
 void dropdown_set_checked(sint32 index, bool value)
 {
-    if (index < 0 || index >= Util::CountOf(_dropdownItemsDisabled))
+    if (index < 0 || index >= (sint32)Util::CountOf(_dropdownItemsDisabled))
     {
         return;
     }
@@ -91,7 +91,7 @@ void dropdown_set_checked(sint32 index, bool value)
 
 void dropdown_set_disabled(sint32 index, bool value)
 {
-    if (index < 0 || index >= Util::CountOf(_dropdownItemsDisabled))
+    if (index < 0 || index >= (sint32)Util::CountOf(_dropdownItemsDisabled))
     {
         return;
     }
diff --git a/src/openrct2/windows/editor_inventions_list.cpp b/src/openrct2/windows/editor_inventions_list.cpp
index d0e068cd29..75bcab5b54 100644
--- a/src/openrct2/windows/editor_inventions_list.cpp
+++ b/src/openrct2/windows/editor_inventions_list.cpp
@@ -666,7 +666,7 @@ static void window_editor_inventions_list_scrollmousedown(rct_window *w, sint32
     if (researchItem == NULL)
         return;
 
-    if (researchItem->entryIndex < (uint32)RESEARCHED_ITEMS_END_2 && research_item_is_always_researched(researchItem))
+    if (researchItem->entryIndex < RESEARCHED_ITEMS_END_2 && research_item_is_always_researched(researchItem))
         return;
 
     window_invalidate(w);
@@ -721,7 +721,7 @@ static void window_editor_inventions_list_cursor(rct_window *w, rct_widgetindex
     if (researchItem == NULL)
         return;
 
-    if (researchItem->entryIndex < (uint32)RESEARCHED_ITEMS_END_2 && research_item_is_always_researched(researchItem)) {
+    if (researchItem->entryIndex < RESEARCHED_ITEMS_END_2 && research_item_is_always_researched(researchItem)) {
         return;
     }
 
diff --git a/src/openrct2/windows/editor_object_selection.cpp b/src/openrct2/windows/editor_object_selection.cpp
index e94b784bdc..c7e5ade57c 100644
--- a/src/openrct2/windows/editor_object_selection.cpp
+++ b/src/openrct2/windows/editor_object_selection.cpp
@@ -1478,7 +1478,7 @@ static void window_editor_object_selection_set_pressed_tab(rct_window *w)
 static void window_editor_object_selection_select_default_objects()
 {
     if (_numSelectedObjectsForType[0] == 0) {
-        for (sint32 i = 0; i < Util::CountOf(DefaultSelectedObjects); i++) {
+        for (sint32 i = 0; i < (sint32)Util::CountOf(DefaultSelectedObjects); i++) {
             window_editor_object_selection_select_object(0, 7, &DefaultSelectedObjects[i]);
         }
     }
@@ -1492,7 +1492,7 @@ static void window_editor_object_selection_select_required_objects()
 {
     sint32 i;
 
-    for (i = 0; i < Util::CountOf(RequiredSelectedObjects); i++)
+    for (i = 0; i < (sint32)Util::CountOf(RequiredSelectedObjects); i++)
         window_editor_object_selection_select_object(0, 0xF, &RequiredSelectedObjects[i]);
 }
 
diff --git a/src/openrct2/windows/new_ride.cpp b/src/openrct2/windows/new_ride.cpp
index bb927f17cf..78af71c0df 100644
--- a/src/openrct2/windows/new_ride.cpp
+++ b/src/openrct2/windows/new_ride.cpp
@@ -303,7 +303,7 @@ static void window_new_ride_populate_list()
     ride_list_item *nextListItem = _windowNewRideListItems;
 
     // For each ride type in the view order list
-    for (sint32 i = 0; i < Util::CountOf(RideTypeViewOrder); i++) {
+    for (sint32 i = 0; i < (sint32)Util::CountOf(RideTypeViewOrder); i++) {
         uint8 rideType = RideTypeViewOrder[i];
         if (rideType == RIDE_TYPE_NULL)
             continue;
@@ -820,7 +820,8 @@ static void window_new_ride_paint(rct_window *w, rct_drawpixelinfo *dpi)
     window_new_ride_draw_tab_images(dpi, w);
 
     if (_windowNewRideCurrentTab != WINDOW_NEW_RIDE_PAGE_RESEARCH) {
-        ride_list_item item = { .ride_type_and_entry = static_cast<uint16>(w->new_ride.highlighted_ride_id)};
+        ride_list_item item;
+        item.ride_type_and_entry = static_cast<uint16>(w->new_ride.highlighted_ride_id);
         if (item.type != RIDE_TYPE_NULL || item.entry_index != 255)
             window_new_ride_paint_ride_information(w, dpi, item, w->x + 3, w->y + w->height - 52, w->width - 6);
     } else {
@@ -994,7 +995,8 @@ static void window_new_ride_paint_ride_information(rct_window *w, rct_drawpixeli
  */
 static void window_new_ride_select(rct_window *w)
 {
-    ride_list_item item = { .ride_type_and_entry = static_cast<uint16>(w->new_ride.selected_ride_id)};
+    ride_list_item item;
+    item.ride_type_and_entry = static_cast<uint16>(w->new_ride.selected_ride_id);
     if (item.type == RIDE_TYPE_NULL)
         return;
 
diff --git a/src/openrct2/windows/park.cpp b/src/openrct2/windows/park.cpp
index 4606d5929e..9260a59d2c 100644
--- a/src/openrct2/windows/park.cpp
+++ b/src/openrct2/windows/park.cpp
@@ -1565,7 +1565,7 @@ static void window_park_objective_paint(rct_window *w, rct_drawpixelinfo *dpi)
 
     // Objective outcome
     if (gScenarioCompletedCompanyValue != MONEY32_UNDEFINED) {
-        if (gScenarioCompletedCompanyValue == 0x80000001) {
+        if ((uint32)gScenarioCompletedCompanyValue == 0x80000001) {
             // Objective failed
             gfx_draw_string_left_wrapped(dpi, NULL, x, y, 222, STR_OBJECTIVE_FAILED, COLOUR_BLACK);
         } else {
diff --git a/src/openrct2/windows/ride.cpp b/src/openrct2/windows/ride.cpp
index aafb0f0a48..5c3e146935 100644
--- a/src/openrct2/windows/ride.cpp
+++ b/src/openrct2/windows/ride.cpp
@@ -3747,7 +3747,7 @@ static void window_ride_maintenance_mousedown(rct_window *w, rct_widgetindex wid
         gDropdownItemsFormat[0] = STR_DROPDOWN_MENU_LABEL;
         gDropdownItemsArgs[0] = STR_DEBUG_FIX_RIDE;
         for (sint32 i = 0; i < 8; i++) {
-            assert(j < Util::CountOf(ride_type->ride_type));
+            assert(j < (sint32)Util::CountOf(ride_type->ride_type));
             if (RideAvailableBreakdowns[ride_type->ride_type[j]] & (uint8)(1 << i)) {
                 if (i == BREAKDOWN_BRAKES_FAILURE && (ride->mode == RIDE_MODE_CONTINUOUS_CIRCUIT_BLOCK_SECTIONED || ride->mode == RIDE_MODE_POWERED_LAUNCH_BLOCK_SECTIONED)) {
                     if (ride->num_vehicles != 1)
@@ -3869,7 +3869,7 @@ static void window_ride_maintenance_dropdown(rct_window *w, rct_widgetindex widg
             sint32 i;
             sint32 num_items = 1;
             for (i = 0; i < 8; i++) {
-                assert(j < Util::CountOf(ride_type->ride_type));
+                assert(j < (sint32)Util::CountOf(ride_type->ride_type));
                 if (RideAvailableBreakdowns[ride_type->ride_type[j]] & (uint8)(1 << i)) {
                     if (i == BREAKDOWN_BRAKES_FAILURE && (ride->mode == RIDE_MODE_CONTINUOUS_CIRCUIT_BLOCK_SECTIONED || ride->mode == RIDE_MODE_POWERED_LAUNCH_BLOCK_SECTIONED)) {
                         if (ride->num_vehicles != 1)
@@ -4233,7 +4233,7 @@ static void window_ride_colour_mousedown(rct_window *w, rct_widgetindex widgetIn
         break;
     case WIDX_ENTRANCE_STYLE_DROPDOWN:
         checkedIndex = -1;
-        for (i = 0; i < Util::CountOf(window_ride_entrance_style_list); i++) {
+        for (i = 0; i < (sint32)Util::CountOf(window_ride_entrance_style_list); i++) {
             gDropdownItemsFormat[i] = STR_DROPDOWN_MENU_LABEL;
             gDropdownItemsArgs[i] = RideEntranceDefinitions[window_ride_entrance_style_list[i]].string_id;
 
diff --git a/src/openrct2/windows/ride_construction.cpp b/src/openrct2/windows/ride_construction.cpp
index 15a4b23a63..a51763a472 100644
--- a/src/openrct2/windows/ride_construction.cpp
+++ b/src/openrct2/windows/ride_construction.cpp
@@ -2517,7 +2517,7 @@ static bool sub_6CA2DF_get_track_element(uint8 *trackElement) {
     }
 
     if (curve <= 8) {
-        for (sint32 i = 0; i < Util::CountOf(gTrackDescriptors); i++) {
+        for (sint32 i = 0; i < (sint32)Util::CountOf(gTrackDescriptors); i++) {
             track_descriptor trackDescriptor = gTrackDescriptors[i];
             if (trackDescriptor.track_curve != curve) continue;
             if (trackDescriptor.starts_diagonal != startsDiagonal) continue;
diff --git a/src/openrct2/windows/viewport.cpp b/src/openrct2/windows/viewport.cpp
index 8d95b5c335..063581616d 100644
--- a/src/openrct2/windows/viewport.cpp
+++ b/src/openrct2/windows/viewport.cpp
@@ -93,7 +93,7 @@ static sint32 _viewportNumber = 1;
 /**
  * Creates a custom viewport window.
  */
-void _window_viewport_open()
+static void _window_viewport_open()
 {
     rct_window *w = window_create_auto_pos(
         INITIAL_WIDTH, INITIAL_HEIGHT,
diff --git a/src/openrct2/windows/water.cpp b/src/openrct2/windows/water.cpp
index 137baaf91d..b492d26667 100644
--- a/src/openrct2/windows/water.cpp
+++ b/src/openrct2/windows/water.cpp
@@ -89,7 +89,7 @@ static rct_window_event_list window_water_events = {
  *
  *  rct2: 0x006E6A40
  */
-void _window_water_open()
+static void _window_water_open()
 {
     rct_window* window;