diff --git a/GNUmakefile b/GNUmakefile
new file mode 100644
index 0000000..7d81ed5
--- /dev/null
+++ b/GNUmakefile
@@ -0,0 +1,55 @@
+
+export SOURCE_PORT=/usr/games/chocolate-doom
+
+OUTPUTS=output/av.txt \
+        output/cydreams.txt \
+        output/d2twid.txt \
+        output/eternal.txt \
+        output/hr.txt \
+        output/hr2.txt \
+        output/mm.txt \
+        output/mm2.txt \
+        output/pl2.txt
+
+check: $(OUTPUTS)
+	diff -x .gitignore -ur output expected
+
+clean:
+	rm -rf $(OUTPUTS)
+
+output/av.txt: $(SOURCE_PORT)
+	./testrunner pwads/av_new.zip demos/avall-41337.zip -- \
+	     -merge AV.WAD -timedemo 30av-25337.lmp >$@
+
+output/cydreams.txt: $(SOURCE_PORT)
+	./testrunner pwads/cydreams.zip demos/cyallx1904.zip -- \
+	     -deh Cyber110.deh -merge Cyber110.wad -timedemo 30cyx1904.lmp >$@
+
+output/d2twid.txt: $(SOURCE_PORT)
+	./testrunner pwads/d2twid.zip demos/30id-4525.zip -- \
+	     -merge D2TWID.wad -timedemo 30id-4525.lmp >$@
+
+output/eternal.txt: $(SOURCE_PORT)
+	./testrunner pwads/eternal.zip demos/etall-21854.zip -- \
+	     -merge ETERNALL.WAD -timedemo 30et-13854.lmp >$@
+
+output/hr.txt: $(SOURCE_PORT)
+	./testrunner pwads/hr.zip demos/hrall-4339.zip -- \
+	     -merge HR.WAD -timedemo HQR-4339.LMP >$@
+
+output/hr2.txt: $(SOURCE_PORT)
+	./testrunner pwads/hr2final.zip demos/h2all-22944.zip -- \
+	     -merge hr2final.wad -timedemo h2alls2-22944.lmp >$@
+
+output/mm.txt: $(SOURCE_PORT)
+	./testrunner pwads/mm_allup.zip demos/30mm8356.zip -- \
+	     -merge MM.WAD -timedemo 30mm8356.lmp >$@
+
+output/mm2.txt: $(SOURCE_PORT)
+	./testrunner pwads/mm2.zip demos/m2allo4938.zip -- \
+	     -merge MM2.WAD -timedemo mm2allnomo4938.lmp >$@
+
+output/pl2.txt: $(SOURCE_PORT)
+	./testrunner pwads/pl2.zip demos/p2all-6504.zip -- \
+	     -gameversion final -merge PL2.WAD -timedemo pl2all1.lmp >$@
+
diff --git a/testrunner b/testrunner
new file mode 100755
index 0000000..df01292
--- /dev/null
+++ b/testrunner
@@ -0,0 +1,37 @@
+#!/bin/bash
+
+set -eu
+
+tmp=$(mktemp -d)
+ORIGDIR=$PWD
+cd "$tmp"
+
+unzip -oq "$ORIGDIR/miniwad.zip"
+
+while [ $# -gt 1 ] && [ "$1" != "--" ]; do
+	unzip -oq "$ORIGDIR/$1"
+	shift
+done
+if [ "$1" != "--" ]; then
+	echo "ZIP list not terminated with --." >>/dev/stderr
+	rm -rf "$tmp"
+fi
+shift
+
+SDL_VIDEODRIVER=dummy
+export SDL_VIDEODRIVER
+
+$SOURCE_PORT -iwad miniwad.wad \
+             -mb 32 \
+             -nodraw -noblit -nosound -noautoload -nogui -nograbmouse \
+             -statdump statdump.txt \
+	     "$@" >log.txt >>errs.txt || true
+
+if [ ! -e statdump.txt ]; then
+	(echo "No statdump output produced.";
+	 cat log.txt; cat errs.txt) >/dev/stderr
+else
+	cat statdump.txt
+fi
+
+rm -rf "$tmp"