diff --git a/project/jni/application/supertux/create-apk-bundle.sh b/project/jni/application/supertux/create-apk-bundle.sh
index 162089c71..88bfc8208 100755
--- a/project/jni/application/supertux/create-apk-bundle.sh
+++ b/project/jni/application/supertux/create-apk-bundle.sh
@@ -1,10 +1,17 @@
 #!/bin/sh
 
+# Set path to your Android keystore and your keystore alias here, or put them in your environment
+[ -z "$ANDROID_KEYSTORE_FILE" ] && ANDROID_KEYSTORE_FILE=~/.android/debug.keystore
+[ -z "$ANDROID_KEYSTORE_ALIAS" ] && ANDROID_KEYSTORE_ALIAS=androiddebugkey
+PASS=
+[ -n "$ANDROID_KEYSTORE_PASS" ] && PASS="--ks-pass env:ANDROID_KEYSTORE_PASS"
+[ -n "$ANDROID_KEYSTORE_PASS_FILE" ] && PASS="--ks-pass file:$ANDROID_KEYSTORE_PASS_FILE"
+
 OUT=`pwd`/../../../../SuperTux-with-data.apk
 rm -f $OUT $OUT-aligned
 cp ../../../../project/app/build/outputs/apk/release/app-release.apk $OUT || exit 1
 cd supertux/data || exit 1
-zip -r -9 $OUT * || exit 1
+zip -r $OUT * || exit 1
 zipalign 4 $OUT $OUT-aligned || exit 1
-apksigner sign --ks $ANDROID_KEYSTORE_FILE --ks-key-alias $ANDROID_KEYSTORE_ALIAS $OUT-aligned || exit 1
+apksigner sign --ks $ANDROID_KEYSTORE_FILE --ks-key-alias $ANDROID_KEYSTORE_ALIAS $PASS $OUT-aligned || exit 1
 mv $OUT-aligned $OUT