diff --git a/README.md b/README.md
index 15cd7c7..3b57aac 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,7 @@ Random single-file programs I've written in my spare time for small tasks.
 * **mkgauss:** Make an array of gaussian blur kernel values with passed radius and sigma. Used for shader development.
 * **mksoundwad:** Program used during the early days of Tim Allen Doom. Deprecated as notsanae now also replaces sounds through an OpenAL hook.
 * **mkssao:** Make an array of SSAO samples. Also for shader development.
+* **mkstartup:** Tool for creating Hexen startup screen graphics. Originally for Demolitionist, now deprecated since full-color graphics can be used.
 * **mkvolume:** Old program for making LUT volume maps.
 * **mkwall:** A program I use on a daily basis to set my wallpaper on every Linux machine.
 * **osnorm:** Experiment for generating object-space normals from an .obj model.
diff --git a/mkstartup.c b/mkstartup.c
new file mode 100644
index 0000000..e2a897e
--- /dev/null
+++ b/mkstartup.c
@@ -0,0 +1,100 @@
+/*
+	mkstartup.c : Makes a Hexen startup screen from provided images.
+	Requires all the files to be in the same folder it's executed in.
+	I didn't bother adding any checks so if this thing catches on fire it's
+	your own damn fault. Add them yourself if you want, this tool was made
+	for personal use anyway.
+
+	Copyright (c) 2020-2022 Marisa the Magician, UnSX Team
+
+	Permission is hereby granted, free of charge, to any person obtaining
+	a copy of this software and associated documentation files (the
+	"Software"), to deal in the Software without restriction, including
+	without limitation the rights to use, copy, modify, merge, publish,
+	distribute, sublicense, and/or sell copies of the Software, and to
+	permit persons to whom the Software is furnished to do so, subject to
+	the following conditions:
+
+	The above copyright notice and this permission notice shall be
+	included in all copies or substantial portions of the Software.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+	IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+	CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+	TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+	SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+#include <stdio.h>
+#include <stdint.h>
+
+int main( void )
+{
+	// we expect everything to be exported straight from gimp in raw image
+	// data format, indexed, no alpha, all graphics must share the same
+	// 16-color palette and have the exact dimensions shown here:
+	//   STARTUP.data     : 640x480, I8 (307200 bytes)
+	//   STARTUP.data.pal : 16 colors, RGB8 (48 bytes)
+	//   NOTCH.data       : 16x23, I8 (368 bytes)
+	//   NETNOTCH.data    : 4x16, I8 (64 bytes)
+	// the NOTCH and NETNOTCH files are optional and their processing will
+	// be skipped if not found
+	uint8_t pal[48] = {0};
+	uint8_t startup[4][38400] = {{0}};
+	uint8_t notch[184] = {0};
+	uint8_t netnotch[32] = {0};
+	uint8_t blk[8] = {0};
+	FILE *fout = fopen("STARTUP.dat","wb");
+	FILE *fin = fopen("STARTUP.data.pal","rb");
+	fread(&pal,1,48,fin);
+	// reduce 8BPC palette to 6BPC
+	for ( int i=0; i<48; i++ )
+		pal[i] = (pal[i]>>2)&0x3f;
+	fwrite(&pal,1,48,fout);
+	fclose(fin);
+	fin = fopen("STARTUP.data","rb");
+	// compose 4-bit planar startup image
+	for ( int i=0; i<38400; i++ )
+	{
+		fread(&blk,1,8,fin);
+		for ( int j=0; j<8; j++ )
+		{
+			startup[0][i] |= !!(blk[j]&1)<<(7-j);
+			startup[1][i] |= !!(blk[j]&2)<<(7-j);
+			startup[2][i] |= !!(blk[j]&4)<<(7-j);
+			startup[3][i] |= !!(blk[j]&8)<<(7-j);
+		}
+	}
+	fclose(fin);
+	fwrite(&startup,1,153600,fout);
+	fclose(fout);
+	fin = fopen("NOTCH.data","rb");
+	if ( !fin ) goto nnotch;
+	fout = fopen("NOTCH.dat","wb");
+	// compose 4-bit linear notch image
+	for ( int i=0; i<184; i++ )
+	{
+		fread(&blk,1,2,fin);
+		notch[i] |= (blk[0]<<4)&0xF0;
+		notch[i] |= blk[1]&0x0F;
+	}
+	fclose(fin);
+	fwrite(&notch,1,184,fout);
+	fclose(fout);
+nnotch:
+	fin = fopen("NETNOTCH.data","rb");
+	if ( !fin ) return 0;
+	fout = fopen("NETNOTCH.dat","wb");
+	// compose 4-bit linear netnotch image
+	for ( int i=0; i<32; i++ )
+	{
+		fread(&blk,1,2,fin);
+		netnotch[i] |= (blk[0]<<4)&0xF0;
+		netnotch[i] |= blk[1]&0x0F;
+	}
+	fclose(fin);
+	fwrite(&netnotch,1,32,fout);
+	fclose(fout);
+	return 0;
+}