diff --git a/th04/player/player.h b/th04/player/player.h
index e28afda6..1e132df1 100644
--- a/th04/player/player.h
+++ b/th04/player/player.h
@@ -11,3 +11,9 @@
 extern motion_t player_pos;
 
 void pascal near player_pos_update_and_clamp(void);
+
+// Shots
+// -----
+#define SHOT_W 16
+#define SHOT_H 16
+// -----
diff --git a/th04/player/player.inc b/th04/player/player.inc
index d4330c79..febf7fa9 100644
--- a/th04/player/player.inc
+++ b/th04/player/player.inc
@@ -9,6 +9,9 @@ PLAYER_OPTION_DISTANCE = (PLAYER_W / 2) + (PLAYER_OPTION_W / 2)
 
 ; Shots
 ; -----
+SHOT_W = 16
+SHOT_H = 16
+
 ; Shots are always fired for multiples of this number of frames, even if
 ; INPUT_SHOT is held for a shorter amount of time.
 SHOT_CYCLE_FRAMES = 18
diff --git a/th04_main.asm b/th04_main.asm
index d0ff964d..0c8b1d09 100644
--- a/th04_main.asm
+++ b/th04_main.asm
@@ -10503,15 +10503,14 @@ loc_104D7:
 		cmp	byte ptr [si], 0
 		jz	short loc_10527
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_1
-		cmp	ax, 0FF80h
+		call	_motion_update_1 pascal, ax
+		cmp	ax, (-(SHOT_W / 2) shl 4)
 		jle	short loc_104F8
-		cmp	ax, 1880h
+		cmp	ax, ((PLAYFIELD_W + (SHOT_W / 2)) shl 4)
 		jge	short loc_104F8
-		cmp	dx, 0FF80h
+		cmp	dx, (-(SHOT_H / 2) shl 4)
 		jle	short loc_104F8
-		cmp	dx, 1780h
+		cmp	dx, ((PLAYFIELD_H + (SHOT_H / 2)) shl 4)
 		jl	short loc_104FD
 
 loc_104F8:
@@ -12710,18 +12709,18 @@ loc_11E5D:
 loc_11E71:
 		cmp	byte_25A27, 1
 		jnz	short loc_11EC1
-		cmp	word_25A28, 0
+		cmp	motion_25A28.cur.x, 0
 		jl	short loc_11EC1
-		cmp	word_25A28, 1800h
+		cmp	motion_25A28.cur.x, 1800h
 		jge	short loc_11EC1
-		cmp	word_25A2A, 0
+		cmp	motion_25A28.cur.y, 0
 		jl	short loc_11EC1
-		cmp	word_25A2A, 1700h
+		cmp	motion_25A28.cur.y, 1700h
 		jge	short loc_11EC1
-		mov	ax, word_25A28
+		mov	ax, motion_25A28.cur.x
 		sar	ax, 4
 		mov	si, ax
-		mov	ax, word_25A2A
+		mov	ax, motion_25A28.cur.y
 		sar	ax, 4
 		add	ax, 0FFF0h
 		mov	di, ax
@@ -13180,7 +13179,7 @@ sub_12247	proc near
 		call	main_01:tiles_invalidate_around pascal, large [_boss_pos.prev]
 		cmp	byte_25A27, 0
 		jz	short loc_1226D
-		call	main_01:tiles_invalidate_around pascal, large [dword_25A2C]
+		call	main_01:tiles_invalidate_around pascal, large [motion_25A28.prev]
 
 loc_1226D:
 		pop	bp
@@ -17929,7 +17928,7 @@ loc_15314:
 		mov	ax, _midboss_pos.cur.x
 		mov	word ptr dword_266E4, ax
 		mov	ax, _midboss_pos.cur.y
-		add	ax, 0FF00h
+		add	ax, (-16 shl 4)
 		mov	word ptr dword_266E4+2,	ax
 		mov	al, byte_255C6
 		mov	ah, 0
@@ -18153,20 +18152,19 @@ var_2		= word ptr -2
 		mov	ax, word_2598A
 		mov	[bp+var_2], ax
 		add	ax, 2
-		push	ax
-		call	_motion_update_2
+		call	_motion_update_2 pascal, ax
 		mov	si, [bp+var_2]
 		cmp	byte ptr [si+20h], 0
 		jz	short loc_15572
-		add	ax, 100h
-		cmp	ax, 1A00h
+		add	ax, (16 shl 4)
+		cmp	ax, ((PLAYFIELD_W + 32) shl 4)
 		jnb	short loc_15586
 
 loc_15572:
 		cmp	byte ptr [si+21h], 0
 		jz	short loc_15582
-		add	dx, 100h
-		cmp	dx, 1900h
+		add	dx, (16 shl 4)
+		cmp	dx, ((PLAYFIELD_H + 32) shl 4)
 		jnb	short loc_15586
 
 loc_15582:
@@ -29966,9 +29964,9 @@ loc_1B9AC:
 		call	snd_se_play pascal, 9
 		mov	byte_25A27, 1
 		mov	ax, _boss_pos.cur.x
-		mov	word_25A28, ax
+		mov	motion_25A28.cur.x, ax
 		mov	ax, _boss_pos.cur.y
-		mov	word_25A2A, ax
+		mov	motion_25A28.cur.y, ax
 		jmp	loc_1BBA4
 ; ---------------------------------------------------------------------------
 
@@ -29982,10 +29980,10 @@ loc_1B9E1:
 		cmp	word_25A34, 50h	; 'P'
 		jnb	short loc_1BA49
 		mov	ax, _player_pos.cur.y
-		sub	ax, word_25A2A
+		sub	ax, motion_25A28.cur.y
 		push	ax
 		mov	ax, _player_pos.cur.x
-		sub	ax, word_25A28
+		sub	ax, motion_25A28.cur.x
 		push	ax
 		call	iatan2
 		mov	[bp+var_1], al
@@ -30029,28 +30027,28 @@ loc_1BA49:
 		add	byte ptr word_25A36+1, al
 
 loc_1BA50:
-		cmp	word_25A28, 400h
+		cmp	motion_25A28.cur.x, 400h
 		jg	short loc_1BA60
 		mov	byte_25A26, 3
 		jmp	loc_1BBA4
 ; ---------------------------------------------------------------------------
 
 loc_1BA60:
-		cmp	word_25A28, 1400h
+		cmp	motion_25A28.cur.x, 1400h
 		jl	short loc_1BA70
 		mov	byte_25A26, 4
 		jmp	loc_1BBA4
 ; ---------------------------------------------------------------------------
 
 loc_1BA70:
-		cmp	word_25A2A, 1300h
+		cmp	motion_25A28.cur.y, 1300h
 		jl	short loc_1BA80
 		mov	byte_25A26, 5
 		jmp	loc_1BBA4
 ; ---------------------------------------------------------------------------
 
 loc_1BA80:
-		cmp	word_25A2A, 200h
+		cmp	motion_25A28.cur.y, 200h
 		jg	loc_1BBA4
 		mov	byte_25A26, 6
 		jmp	loc_1BBA4
@@ -30116,10 +30114,10 @@ loc_1BB0C:
 
 loc_1BB14:
 		mov	ax, _boss_pos.cur.y
-		sub	ax, word_25A2A
+		sub	ax, motion_25A28.cur.y
 		push	ax
 		mov	ax, _boss_pos.cur.x
-		sub	ax, word_25A28
+		sub	ax, motion_25A28.cur.x
 		push	ax
 		call	iatan2
 		mov	byte ptr word_25A36, al
@@ -30128,19 +30126,19 @@ loc_1BB14:
 		mov	byte ptr word_25A36+1, al
 		mov	ax, _boss_pos.cur.x
 		add	ax, (-16 shl 4)
-		cmp	ax, word_25A28
+		cmp	ax, motion_25A28.cur.x
 		jge	short loc_1BBA8
 		mov	ax, _boss_pos.cur.x
 		add	ax, (16 shl 4)
-		cmp	ax, word_25A28
+		cmp	ax, motion_25A28.cur.x
 		jle	short loc_1BBA8
 		mov	ax, _boss_pos.cur.y
 		add	ax, (-16 shl 4)
-		cmp	ax, word_25A2A
+		cmp	ax, motion_25A28.cur.y
 		jge	short loc_1BBA8
 		mov	ax, _boss_pos.cur.y
 		add	ax, (16 shl 4)
-		cmp	ax, word_25A2A
+		cmp	ax, motion_25A28.cur.y
 		jle	short loc_1BBA8
 		mov	byte_25A26, 8
 		mov	byte_25A27, 2
@@ -30172,9 +30170,9 @@ loc_1BBA8:
 		cmp	byte_25A27, 1
 		jnz	short locret_1BC2A
 		push	ds
-		push	offset unk_25A30
+		push	offset motion_25A28.velocity.x
 		push	ds
-		push	offset word_25A32
+		push	offset motion_25A28.velocity.y
 		push	word_25A36
 		mov	al, byte ptr word_25A36+1
 		mov	ah, 0
@@ -30182,31 +30180,30 @@ loc_1BBA8:
 		call	vector2
 		mov	word_257E2, 200h
 		mov	word_257E4, 200h
-		mov	ax, word_25A28
+		mov	ax, motion_25A28.cur.x
 		mov	word ptr dword_257DE, ax
-		mov	ax, word_25A2A
+		mov	ax, motion_25A28.cur.y
 		mov	word ptr dword_257DE+2,	ax
 		call	sub_105B9
 		shr	ax, 1
-		mov	dx, word_25A32
+		mov	dx, motion_25A28.velocity.y
 		sub	dx, ax
-		mov	word_25A32, dx
-		push	46E8h
-		call	_motion_update_2
-		mov	ax, word_25A28
-		add	ax, 0FE80h
+		mov	motion_25A28.velocity.y, dx
+		call	_motion_update_2 pascal, offset motion_25A28
+		mov	ax, motion_25A28.cur.x
+		add	ax, (-24 shl 4)
 		cmp	ax, _player_pos.cur.x
 		jge	short locret_1BC2A
-		mov	ax, word_25A28
-		add	ax, 180h
+		mov	ax, motion_25A28.cur.x
+		add	ax, (24 shl 4)
 		cmp	ax, _player_pos.cur.x
 		jle	short locret_1BC2A
-		mov	ax, word_25A2A
-		add	ax, 0FE80h
+		mov	ax, motion_25A28.cur.y
+		add	ax, (-24 shl 4)
 		cmp	ax, _player_pos.cur.y
 		jge	short locret_1BC2A
-		mov	ax, word_25A2A
-		add	ax, 180h
+		mov	ax, motion_25A28.cur.y
+		add	ax, (24 shl 4)
 		cmp	ax, _player_pos.cur.y
 		jle	short locret_1BC2A
 		mov	byte_259A9, 1
@@ -31910,15 +31907,14 @@ loc_1CA17:
 
 loc_1CA27:
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_2
-		cmp	ax, 0FF80h
+		call	_motion_update_2 pascal, ax
+		cmp	ax, (-8 shl 4)
 		jle	short loc_1CA43
-		cmp	ax, 1880h
+		cmp	ax, ((PLAYFIELD_W + 8) shl 4)
 		jge	short loc_1CA43
-		cmp	dx, 0FF80h
+		cmp	dx, (-8 shl 4)
 		jle	short loc_1CA43
-		cmp	dx, 1780h
+		cmp	dx, ((PLAYFIELD_H + 8) shl 4)
 		jl	short loc_1CA49
 
 loc_1CA43:
@@ -40623,12 +40619,7 @@ byte_25A24	db ?
 		db ?
 byte_25A26	db ?
 byte_25A27	db ?
-word_25A28	dw ?
-word_25A2A	dw ?
-dword_25A2C	dd ?
-unk_25A30	db    ?	;
-		db    ?	;
-word_25A32	dw ?
+motion_25A28	motion_t <?>
 word_25A34	dw ?
 word_25A36	dw ?
 byte_25A38	db ?
diff --git a/th05_main.asm b/th05_main.asm
index 5d1339d2..8cb969cf 100644
--- a/th05_main.asm
+++ b/th05_main.asm
@@ -11431,15 +11431,14 @@ loc_11568:
 		cmp	byte ptr [si], 0
 		jz	short loc_115CE
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_1
-		cmp	ax, 0FF80h
+		call	_motion_update_1 pascal, ax
+		cmp	ax, (-8 shl 4)
 		jle	short loc_11589
-		cmp	ax, 1880h
+		cmp	ax, ((PLAYFIELD_W + 8) shl 4)
 		jge	short loc_11589
-		cmp	dx, 0FF80h
+		cmp	dx, (-8 shl 4)
 		jle	short loc_11589
-		cmp	dx, 1780h
+		cmp	dx, ((PLAYFIELD_H + 8) shl 4)
 		jl	short loc_1158F
 
 loc_11589:
@@ -12905,15 +12904,14 @@ shots_update_missile_straight:
 
 loc_124FA:
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_1
-		cmp	ax, 0FF80h
+		call	_motion_update_1 pascal, ax
+		cmp	ax, (-(SHOT_W / 2) shl 4)
 		jle	short loc_12516
-		cmp	ax, 1880h
+		cmp	ax, ((PLAYFIELD_W + (SHOT_W / 2)) shl 4)
 		jge	short loc_12516
-		cmp	dx, 0FF80h
+		cmp	dx, (-(SHOT_H / 2) shl 4)
 		jle	short loc_12516
-		cmp	dx, 1780h
+		cmp	dx, ((PLAYFIELD_H + (SHOT_H / 2)) shl 4)
 		jl	short loc_1251B
 
 loc_12516:
@@ -14233,19 +14231,18 @@ MOTION_UPDATE_DEF 2
 
 sub_152F2	proc near
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_2
+		call	_motion_update_2 pascal, ax
 		test	byte ptr [si+1Fh], 1
 		jz	short loc_15307
-		add	ax, 100h
-		cmp	ax, 1A00h
+		add	ax, (16 shl 4)
+		cmp	ax, (416 shl 4)
 		jnb	short loc_15319
 
 loc_15307:
 		test	byte ptr [si+1Fh], 10h
 		jz	short loc_15317
-		add	dx, 100h
-		cmp	dx, 1900h
+		add	dx, (16 shl 4)
+		cmp	dx, (400 shl 4)
 		jnb	short loc_15319
 
 loc_15317:
@@ -19201,15 +19198,14 @@ loc_17D93:
 
 loc_17DA3:
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_2
-		cmp	ax, 0FF80h
+		call	_motion_update_2 pascal, ax
+		cmp	ax, (-8 shl 4)
 		jle	short loc_17DBF
-		cmp	ax, 1880h
+		cmp	ax, ((PLAYFIELD_W + 8) shl 4)
 		jge	short loc_17DBF
-		cmp	dx, 0FF80h
+		cmp	dx, (-8 shl 4)
 		jle	short loc_17DBF
-		cmp	dx, 1780h
+		cmp	dx, ((PLAYFIELD_H + 8) shl 4)
 		jl	short loc_17DC5
 
 loc_17DBF:
@@ -19226,11 +19222,11 @@ loc_17DC5:
 		jnz	short loc_17E41
 		cmp	byte ptr [si+12h], 0
 		jz	short loc_17DFE
-		add	ax, 40h
-		cmp	ax, 80h
+		add	ax, (4 shl 4)
+		cmp	ax, (8 shl 4)
 		ja	short loc_17E41
-		add	dx, 40h
-		cmp	dx, 80h
+		add	dx, (4 shl 4)
+		cmp	dx, (8 shl 4)
 		ja	short loc_17E41
 		mov	byte ptr [si], 2
 		mov	_player_is_hit, 1
@@ -19238,11 +19234,11 @@ loc_17DC5:
 ; ---------------------------------------------------------------------------
 
 loc_17DFE:
-		add	ax, 100h
-		cmp	ax, 240h
+		add	ax, (16 shl 4)
+		cmp	ax, (36 shl 4)
 		ja	short loc_17E41
-		add	dx, 160h
-		cmp	dx, 2C0h
+		add	dx, (22 shl 4)
+		cmp	dx, (44 shl 4)
 		ja	short loc_17E41
 		push	word ptr [si+2]
 		push	word ptr [si+4]
@@ -25372,15 +25368,14 @@ loc_1B461:
 		jz	loc_1B548
 		inc	word ptr [si+0Eh]
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_2
+		call	_motion_update_2 pascal, ax
 		cmp	ax, (-16 shl 4)
 		jle	short loc_1B488
-		cmp	ax, 1900h
+		cmp	ax, ((PLAYFIELD_W + 16) shl 4)
 		jge	short loc_1B488
 		cmp	dx, (-16 shl 4)
 		jle	short loc_1B488
-		cmp	dx, 1800h
+		cmp	dx, ((PLAYFIELD_H + 16) shl 4)
 		jl	short loc_1B48B
 
 loc_1B488:
@@ -27654,15 +27649,14 @@ loc_1C90C:
 
 loc_1C920:
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_2
+		call	_motion_update_2 pascal, ax
 		cmp	ax, (-16 shl 4)
 		jle	short loc_1C93D
-		cmp	ax, 1900h
+		cmp	ax, ((PLAYFIELD_W + 16) shl 4)
 		jge	short loc_1C93D
 		cmp	dx, (-16 shl 4)
 		jle	short loc_1C93D
-		cmp	dx, 1800h
+		cmp	dx, ((PLAYFIELD_H + 16) shl 4)
 		jl	short loc_1C93F
 
 loc_1C93D:
@@ -28962,15 +28956,14 @@ loc_1D5C2:
 loc_1D5C5:
 		inc	word ptr [si+0Eh]
 		lea	ax, [si+2]
-		push	ax
-		call	_motion_update_2
+		call	_motion_update_2 pascal, ax
 		cmp	ax, (-16 shl 4)
 		jle	short loc_1D5E5
-		cmp	ax, 1900h
+		cmp	ax, ((PLAYFIELD_W + 16) shl 4)
 		jge	short loc_1D5E5
 		cmp	dx, (-16 shl 4)
 		jle	short loc_1D5E5
-		cmp	dx, 1800h
+		cmp	dx, ((PLAYFIELD_H + 16) shl 4)
 		jl	short loc_1D5E7
 
 loc_1D5E5: