diff --git a/th04/main/ems.h b/th04/main/ems.h
deleted file mode 100644
index dc2a9c20..00000000
--- a/th04/main/ems.h
+++ /dev/null
@@ -1 +0,0 @@
-extern seg_t Ems; /* ZUN symbol [MAGNet2010] */
diff --git a/th04/main/ems.hpp b/th04/main/ems.hpp
new file mode 100644
index 00000000..b315732e
--- /dev/null
+++ b/th04/main/ems.hpp
@@ -0,0 +1,55 @@
+/// EMS cache area
+/// --------------
+/// Stores situational .CDG images that can later be copied into conventional
+/// memory as needed.
+/// (Yes, this is not how you make optimal use of EMS memory.)
+
+#if (GAME == 5)
+	#define EMS_NAME "GENSOEMS"
+#else
+	#define EMS_NAME "KAIKIEMS"
+#endif
+
+// Layout
+// ------
+// This is technically a structure of Planar<dots8_t[]> elements with the
+// given size. But since such a structure would exceed 64 KiB, we can't declare
+// it as such for a 16-bit compiler. Using an enum won't work either, as Turbo
+// C++ 4.0J silently degrades any signed 32-bit values to signed 16-bit ones
+// at compile time. That only leaves constants, unfortunately.
+// MODDERS: Just remove the needless assignments of hardcoded offset values,
+// they only provide unnecessary (and unsafe) padding. Define them in terms of
+// their predecessor instead.
+
+#define sizeof_planar_rect(w, h) \
+	((((w) / BYTE_DOTS) * h) * static_cast<uint32_t>(PLANE_COUNT))
+
+static const uint32_t EMS_EYECATCH_OFFSET = 0;
+static const uint32_t EMS_EYECATCH_END = (
+	EMS_EYECATCH_OFFSET + sizeof_planar_rect(EYECATCH_W, EYECATCH_H)
+);
+static const uint32_t EMS_PLAYCHAR_BOMB_BG_OFFSET = 34000;
+static const uint32_t EMS_PLAYCHAR_BOMB_BG_END = (EMS_PLAYCHAR_BOMB_BG_OFFSET +
+	sizeof_planar_rect(BOMB_BG_W_MAX, BOMB_BG_H_MAX)
+);
+#if (GAME == 5)
+	static const uint32_t EMS_FACESET_PLAYCHAR_OFFSET = 100000;
+#else
+	static const uint32_t EMS_FACESET_PLAYCHAR_OFFSET = 94000;
+#endif
+static const uint32_t EMS_FACESET_PLAYCHAR_END = (EMS_FACESET_PLAYCHAR_OFFSET +
+	(FACESET_PLAYCHAR_COUNT * sizeof_planar_rect(FACE_W, FACE_H))
+);
+#if (GAME == 5)
+	static const uint32_t EMS_FACESET_BOSS_OFFSET = 200000;
+	static const uint32_t EMS_FACESET_BOSS_END = (EMS_FACESET_BOSS_OFFSET +
+		(FACESET_BOSS_COUNT * sizeof_planar_rect(FACE_W, FACE_H))
+	);
+	static const uint32_t EMSSIZE = 320000; /* ZUN symbol [MAGNet2010] */
+#else
+	static const uint32_t EMSSIZE = 180000; /* ZUN symbol [MAGNet2010] */
+#endif
+// ------
+
+extern seg_t Ems; /* ZUN symbol [MAGNet2010] */
+/// --------------
diff --git a/th04/mem.h b/th04/mem.h
index 5f8c3db4..c4d49cf7 100644
--- a/th04/mem.h
+++ b/th04/mem.h
@@ -3,6 +3,4 @@
 #define MEM_ASSIGN_PARAS_MAIN  (320000 >> 4)
 #define MEM_ASSIGN_PARAS_MAINE (336000 >> 4)
 
-#define EMSSIZE (180000) /* ZUN symbol [MAGNet2010] */
-
 #define DEMO_N 4000 /* ZUN symbol [MAGNet2010] */
diff --git a/th04/sprites/main_cdg.h b/th04/sprites/main_cdg.h
index 9247ca47..69f7dd50 100644
--- a/th04/sprites/main_cdg.h
+++ b/th04/sprites/main_cdg.h
@@ -1,10 +1,25 @@
 #define FACESET_PLAYCHAR_COUNT 6
 #if (GAME == 5)
 	#define FACESET_BOSS_COUNT 6
+
+	#define EYECATCH_W 288
+	#define EYECATCH_H 130
+
+	#define BOMB_BG_W_MAX ((PLAYFIELD_W / 6) * 5)
+	#define BOMB_BG_H_MAX PLAYFIELD_H
 #else
 	#define FACESET_BOSS_COUNT 4
+
+	#define EYECATCH_W 384
+	#define EYECATCH_H 176
+
+	#define BOMB_BG_W_MAX PLAYFIELD_W
+	#define BOMB_BG_H_MAX (PLAYFIELD_H - 94)
 #endif
 
+#define FACE_W 128
+#define FACE_H 128
+
 // CDG slots for TH04's and TH05's MAIN.EXE.
 typedef enum {
 	CDG_BG_PLAYCHAR_BOMB = 0,
diff --git a/th04/sprites/main_cdg.inc b/th04/sprites/main_cdg.inc
index 2cdd9fe8..4642dfda 100644
--- a/th04/sprites/main_cdg.inc
+++ b/th04/sprites/main_cdg.inc
@@ -5,6 +5,9 @@ else
 	FACESET_BOSS_COUNT = 4
 endif
 
+FACE_W = 128
+FACE_H = 128
+
 CDG_BG_PLAYCHAR_BOMB = 0
 CDG_PER_STAGE = 1
 CDG_FACESET_PLAYCHAR = 2
diff --git a/th05/mem.h b/th05/mem.h
index b9059ef7..e8172c66 100644
--- a/th05/mem.h
+++ b/th05/mem.h
@@ -3,6 +3,4 @@
 #define MEM_ASSIGN_PARAS_MAIN  (291200 >> 4)
 #define MEM_ASSIGN_PARAS_MAINE (336000 >> 4)
 
-#define EMSSIZE (320000) /* ZUN symbol [MAGNet2010] */
-
 #define DEMO_N 5000 /* ZUN symbol [MAGNet2010] */