diff --git a/scripts/src/3rdparty.lua b/scripts/src/3rdparty.lua
index 7666f4d9e09..9666b7563bb 100644
--- a/scripts/src/3rdparty.lua
+++ b/scripts/src/3rdparty.lua
@@ -720,6 +720,7 @@ end
 		buildoptions {
 			"-Wno-uninitialized",
 			"-Wno-unused-function",
+			"-Wno-unused-but-set-variable",
 		}
 	configuration { "rpi" }
 		buildoptions {
@@ -788,8 +789,17 @@ end
 		MAME_DIR .. "3rdparty/bgfx/examples/common/font/text_metrics.cpp",
 		MAME_DIR .. "3rdparty/bgfx/examples/common/font/utf8.cpp",
 		MAME_DIR .. "3rdparty/bgfx/examples/common/imgui/imgui.cpp",
+		MAME_DIR .. "3rdparty/bgfx/examples/common/imgui/ocornut_imgui.cpp",
+		MAME_DIR .. "3rdparty/bgfx/examples/common/imgui/scintilla.cpp",
 		MAME_DIR .. "3rdparty/bgfx/examples/common/nanovg/nanovg.cpp",
 		MAME_DIR .. "3rdparty/bgfx/examples/common/nanovg/nanovg_bgfx.cpp",
+		MAME_DIR .. "3rdparty/bgfx/3rdparty/ib-compress/indexbuffercompression.cpp",
+		MAME_DIR .. "3rdparty/bgfx/3rdparty/ib-compress/indexbufferdecompression.cpp",
+		MAME_DIR .. "3rdparty/bgfx/3rdparty/ocornut-imgui/imgui.cpp",
+		MAME_DIR .. "3rdparty/bgfx/3rdparty/ocornut-imgui/imgui_demo.cpp",
+		MAME_DIR .. "3rdparty/bgfx/3rdparty/ocornut-imgui/imgui_draw.cpp",
+		MAME_DIR .. "3rdparty/bgfx/3rdparty/ocornut-imgui/imgui_node_graph_test.cpp",
+		MAME_DIR .. "3rdparty/bgfx/3rdparty/ocornut-imgui/imgui_wm.cpp",
 	}
 	if _OPTIONS["targetos"]=="macosx" then
 		files {
diff --git a/scripts/src/osd/modules.lua b/scripts/src/osd/modules.lua
index d50f12745d4..f955659908d 100644
--- a/scripts/src/osd/modules.lua
+++ b/scripts/src/osd/modules.lua
@@ -74,7 +74,7 @@ function osdmodulesbuild()
 		MAME_DIR .. "src/osd/modules/input/input_common.cpp",
 		MAME_DIR .. "src/osd/modules/input/input_common.h",
 		MAME_DIR .. "src/osd/modules/input/input_dinput.cpp",
-    MAME_DIR .. "src/osd/modules/input/input_dinput.h",
+		MAME_DIR .. "src/osd/modules/input/input_dinput.h",
 		MAME_DIR .. "src/osd/modules/input/input_none.cpp",
 		MAME_DIR .. "src/osd/modules/input/input_rawinput.cpp",
 		MAME_DIR .. "src/osd/modules/input/input_win32.cpp",
@@ -129,6 +129,7 @@ function osdmodulesbuild()
 		"__STDC_LIMIT_MACROS",
 		"__STDC_FORMAT_MACROS",
 		"__STDC_CONSTANT_MACROS",
+		"IMGUI_DISABLE_OBSOLETE_FUNCTIONS",
 	}
 
 	files {
@@ -172,7 +173,9 @@ function osdmodulesbuild()
 		MAME_DIR .. "src/osd/modules/render/bgfx/writereader.cpp",
 	}
 	includedirs {
+		MAME_DIR .. "3rdparty/bgfx/examples/common",
 		MAME_DIR .. "3rdparty/bgfx/include",
+		MAME_DIR .. "3rdparty/bgfx/3rdparty",
 		MAME_DIR .. "3rdparty/bx/include",
 		MAME_DIR .. "3rdparty/rapidjson/include",
 	}
diff --git a/src/devices/bus/kc/rom.cpp b/src/devices/bus/kc/rom.cpp
index 404089110a0..883b36eb739 100644
--- a/src/devices/bus/kc/rom.cpp
+++ b/src/devices/bus/kc/rom.cpp
@@ -43,7 +43,7 @@ const device_type KC_M033     = &device_creator<kc_m033_device>;
 //-------------------------------------------------
 
 kc_8k_device::kc_8k_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
-		: device_t(mconfig, KC_STANDARD, "Standard", tag, owner, clock, "kc_8k", __FILE__),
+		: device_t(mconfig, KC_STANDARD, "Standard 8K ROM module", tag, owner, clock, "kc_8k", __FILE__),
 		device_kcexp_interface( mconfig, *this ), m_slot(nullptr), m_mei(0), m_rom(nullptr), m_enabled(0), m_base(0)
 	{
 }
diff --git a/src/mame/video/bbusters.cpp b/src/mame/video/bbusters.cpp
index 1a090935c17..0e7362fd085 100644
--- a/src/mame/video/bbusters.cpp
+++ b/src/mame/video/bbusters.cpp
@@ -200,18 +200,20 @@ void bbusters_state::draw_sprites(bitmap_ind16 &bitmap, const UINT16 *source, in
 	int offs;
 
 	for (offs = 0;offs <0x800 ;offs += 4) {
-		int x,y,sprite,colour,fx,fy,scale;
+		int x,sprite,colour,fx,fy,scale;
+		INT16 y;
 		int block;
 
 		sprite=source[offs+1];
 		colour=source[offs+0];
 
-		if (colour==0xf7 && (sprite==0x3fff || sprite==0xffff))
-			continue;
+		if ((colour==0xf7 || colour==0xffff || colour == 0x43f9) && (sprite==0x3fff || sprite==0xffff || sprite==0x0001))
+			continue; // sprite 1, color 0x43f9 is the dead sprite in the top-right of the screen in Mechanized Attack's High Score table.
 
 		y=source[offs+3];
 		x=source[offs+2];
 		if (x&0x200) x=-(0x100-(x&0xff));
+		if (y > 320 || y < -256) y &= 0x1ff; // fix for bbusters ending & "Zing!" attract-mode fullscreen zombie & Helicopter on the 3rd rotation of the attractmode sequence
 
 		/*
 		    Source[0]:
diff --git a/src/osd/modules/render/drawbgfx.cpp b/src/osd/modules/render/drawbgfx.cpp
index 415e5ef33e4..4798bdbd4b6 100644
--- a/src/osd/modules/render/drawbgfx.cpp
+++ b/src/osd/modules/render/drawbgfx.cpp
@@ -43,6 +43,8 @@
 #include "bgfx/slider.h"
 #include "bgfx/target.h"
 
+#include "imgui/imgui.h"
+
 //============================================================
 //  DEBUGGING
 //============================================================
@@ -198,6 +200,8 @@ int renderer_bgfx::create()
 	memset(m_white, 0xff, sizeof(uint32_t) * 16 * 16);
 	m_texinfo.push_back(rectangle_packer::packable_rectangle(WHITE_HASH, PRIMFLAG_TEXFORMAT(TEXFORMAT_ARGB32), 16, 16, 16, nullptr, m_white));
 
+	imguiCreate();
+
 	return 0;
 }
 
@@ -261,6 +265,8 @@ renderer_bgfx::~renderer_bgfx()
 
 void renderer_bgfx::exit()
 {
+	imguiDestroy();
+
 	bgfx::shutdown();
 	s_window_set = false;
 }