diff --git a/src/cvars.cpp b/src/cvars.cpp
index 112263f81..8668c27f4 100644
--- a/src/cvars.cpp
+++ b/src/cvars.cpp
@@ -538,6 +538,7 @@ consvar_t cv_maxping = Server("maxdelay", "20").values(CV_Unsigned);
 consvar_t cv_menujam = Server("menujam", "menu").values({{0, "menu"}, {1, "menu2"}, {2, "menu3"}});
 consvar_t cv_menujam_update = Server("menujam_update", "Off").on_off();
 consvar_t cv_netdemosyncquality = Server("netdemo_syncquality", "1").min_max(1, 35);
+consvar_t cv_netdemosize = Server("netdemo_size", "6").values(CV_Natural);
 
 void NetTimeout_OnChange(void);
 consvar_t cv_nettimeout = Server("nettimeout", "210").min_max(TICRATE/7, 60*TICRATE).onchange(NetTimeout_OnChange);
diff --git a/src/doomdef.h b/src/doomdef.h
index ffec260ef..21e8bdb4f 100644
--- a/src/doomdef.h
+++ b/src/doomdef.h
@@ -548,6 +548,7 @@ typedef enum
 	DBG_SETUP			= 0x00000400,
 	DBG_LUA				= 0x00000800,
 	DBG_RNG				= 0x00001000,
+	DBG_DEMO			= 0x00002000,
 } debugFlags_t;
 
 struct debugFlagNames_s
diff --git a/src/g_demo.c b/src/g_demo.c
index 4b51c85d7..b0f539f9c 100644
--- a/src/g_demo.c
+++ b/src/g_demo.c
@@ -734,6 +734,7 @@ void G_GhostAddHit(INT32 playernum, mobj_t *victim)
 
 void G_WriteAllGhostTics(void)
 {
+	boolean toobig = false;
 	INT32 i, counter = leveltime;
 	for (i = 0; i < MAXPLAYERS; i++)
 	{
@@ -750,12 +751,18 @@ void G_WriteAllGhostTics(void)
 
 		WRITEUINT8(demobuf.p, i);
 		G_WriteGhostTic(players[i].mo, i);
+
+		// attention here for the ticcmd size!
+		// latest demos with mouse aiming byte in ticcmd
+		if (demobuf.p >= demobuf.end - (13 + 9 + 9))
+		{
+			toobig = true;
+			break;
+		}
 	}
 	WRITEUINT8(demobuf.p, 0xFF);
 
-	// attention here for the ticcmd size!
-	// latest demos with mouse aiming byte in ticcmd
-	if (demobuf.p >= demobuf.end - (13 + 9 + 9))
+	if (toobig)
 	{
 		G_CheckDemoStatus(); // no more space
 		return;
@@ -2088,16 +2095,13 @@ void G_WriteMetalTic(mobj_t *metal)
 //
 void G_RecordDemo(const char *name)
 {
+	extern consvar_t cv_netdemosize;
+
 	INT32 maxsize;
 
 	strcpy(demoname, name);
 	strcat(demoname, ".lmp");
-	//@TODO make a maxdemosize cvar
-	// NOPE. We are kicking this can HELLA down the road. -Tyron 2024-01-20
-	maxsize = 1024*1024*4;
-
-	if (M_CheckParm("-maxdemo") && M_IsNextParm())
-		maxsize = atoi(M_GetNextParm()) * 1024;
+	maxsize = 1024 * 1024 * cv_netdemosize.value;
 
 //	if (demobuf.buffer)
 //		Z_Free(demobuf.buffer);
@@ -2109,6 +2113,21 @@ void G_RecordDemo(const char *name)
 	demobuf.p = NULL;
 
 	demo.recording = true;
+	demo.buffer = &demobuf;
+
+	/* FIXME: This whole file is in a wretched state. Take a
+	look at G_WriteAllGhostTics and G_WriteDemoTiccmd, they
+	write a lot of data. It's not realistic to refactor that
+	code in order to know exactly HOW MANY bytes it can write
+	out. So here's the deal. Reserve a decent block of memory
+	at the end of the buffer and never use it. Those bastard
+	functions will check if they overran the buffer, but it
+	should be safe enough because they'll think there's less
+	memory than there actually is and stop early. */
+	const size_t deadspace = 1024;
+	I_Assert(demobuf.size > deadspace);
+	demobuf.size -= deadspace;
+	demobuf.end -= deadspace;
 }
 
 void G_RecordMetal(void)
@@ -3246,6 +3265,7 @@ void G_DoPlayDemo(const char *defdemoname)
 	// read demo header
 	gameaction = ga_nothing;
 	demo.playback = true;
+	demo.buffer = &demobuf;
 	if (memcmp(demobuf.p, DEMOHEADER, 12))
 	{
 		snprintf(msg, 1024, M_GetText("%s is not a Ring Racers replay file.\n"), pdemoname);
diff --git a/src/g_demo.h b/src/g_demo.h
index f102e8517..e19f8f820 100644
--- a/src/g_demo.h
+++ b/src/g_demo.h
@@ -65,6 +65,8 @@ struct demovars_s {
 	UINT8 numskins;
 	democharlist_t *skinlist;
 	UINT8 currentskinid[MAXPLAYERS];
+
+	const savebuffer_t *buffer; // debug, valid only if recording or playback
 };
 
 extern struct demovars_s demo;
diff --git a/src/k_menu.h b/src/k_menu.h
index da1b68f61..a623aedb3 100644
--- a/src/k_menu.h
+++ b/src/k_menu.h
@@ -342,6 +342,7 @@ typedef enum
 	dopt_replay,
 	dopt_rprecord,
 	dopt_rpsync,
+	dopt_rpsize,
 #ifdef HAVE_DISCORDRPC
 	dopt_discord,
 	dopt_drp,
diff --git a/src/m_cheat.c b/src/m_cheat.c
index f9eb97cd8..c623a8f1e 100644
--- a/src/m_cheat.c
+++ b/src/m_cheat.c
@@ -605,6 +605,8 @@ struct debugFlagNames_s const debug_flag_names[] =
 	{"Music", DBG_MUSIC},
 	{"PwrLv", DBG_PWRLV},
 	{"PowerLevel", DBG_PWRLV}, // alt name
+	{"Demo", DBG_DEMO},
+	{"Replay", DBG_DEMO}, // alt name
 	{NULL, 0}
 };
 
diff --git a/src/menus/options-data-1.c b/src/menus/options-data-1.c
index 97393948a..fd7f830d6 100644
--- a/src/menus/options-data-1.c
+++ b/src/menus/options-data-1.c
@@ -4,6 +4,8 @@
 #include "../k_menu.h"
 #include "../discord.h" // discord rpc cvars
 
+extern consvar_t cv_netdemosize;
+
 // data options menu -- see dopt_e
 menuitem_t OPTIONS_Data[] =
 {
@@ -26,6 +28,9 @@ menuitem_t OPTIONS_Data[] =
 	{IT_STRING | IT_CVAR, "Net Consistency Quality", "For filesize, how often do we write position data in online replays?",
 		NULL, {.cvar = &cv_netdemosyncquality}, 0, 0},
 
+	{IT_STRING | IT_CVAR, "Buffer Size (MB)", "Lets replays last longer with more players. Uses more RAM.",
+		NULL, {.cvar = &cv_netdemosize}, 0, 0},
+
 #ifdef HAVE_DISCORDRPC
 	{IT_HEADER, "Discord Rich Presence...", NULL,
 		NULL, {NULL}, 0, 0},
diff --git a/src/st_stuff.c b/src/st_stuff.c
index 50e3ba29f..8e2505ef5 100644
--- a/src/st_stuff.c
+++ b/src/st_stuff.c
@@ -448,6 +448,31 @@ static void ST_drawRenderDebug(INT32 *height)
 	ST_pushDebugString(height, va("Skybox Portals: %4s", sizeu1(i->skybox_portals)));
 }
 
+static void ST_drawDemoDebug(INT32 *height)
+{
+	if (!demo.recording && !demo.playback)
+		return;
+
+	size_t needle = demo.buffer->p - demo.buffer->buffer;
+	size_t size = demo.buffer->size;
+	double percent = (double)needle / size * 100.0;
+	double avg = (double)needle / leveltime;
+
+	ST_pushDebugString(height, va("%s/%s bytes", sizeu1(needle), sizeu2(size)));
+	ST_pushDebugString(height, va(
+			"%.2f/%.2f MB %5.2f%%",
+			needle / (1024.0 * 1024.0),
+			size / (1024.0 * 1024.0),
+			percent
+	));
+	ST_pushDebugString(height, va(
+			"%.2f KB/s (ETA %.2f minutes)",
+			avg * TICRATE / 1024.0,
+			(size - needle) / (avg * TICRATE * 60.0)
+	));
+	ST_pushDebugString(height, va("Demo (%s)", demo.recording ? "recording" : "playback"));
+}
+
 void ST_drawDebugInfo(void)
 {
 	INT32 height = 192;
@@ -547,6 +572,11 @@ void ST_drawDebugInfo(void)
 		ST_drawRenderDebug(&height);
 	}
 
+	if (cht_debug & DBG_DEMO)
+	{
+		ST_drawDemoDebug(&height);
+	}
+
 	if (cht_debug & DBG_MEMORY)
 		V_DrawRightAlignedString(320, height,     V_MONOSPACE, va("Heap used: %7sKB", sizeu1(Z_TagsUsage(0, INT32_MAX)>>10)));
 }