diff --git a/README.md b/README.md
index 924b880..763a750 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,8 @@ moving onto boxes makes you enter them. right now, this doesn't change your posi
 
 moving out of bounds makes you exit the box, if you're in one. this also doesn't change your position yet. if you exit at a position where there's another box in the one you exit into, you'll immediately enter that box.
 
+there's a demo video at `/assets/demo_video.webm`.
+
 # controls
 
 - arrow keys: move around.
diff --git a/assets/demo_video.webm b/assets/demo_video.webm
new file mode 100644
index 0000000..b96b066
Binary files /dev/null and b/assets/demo_video.webm differ