diff --git a/README.md b/README.md
index 66c893a..270b84e 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,9 @@ To generate the full set, just run `make` (you may want to run `make clean` if y
  * GNU Make
  * imagemagick
  * png2icns (provided on Ubuntu by `icnsutils`, or [via sourceforge](http://icns.sourceforge.net/))
+ * pngcrush
+ * unzip
+ * zip
 
 
 [1]: https://www.gosquared.com/resources/flag-icons