diff --git a/README.md b/README.md
index db64aab..1759082 100644
--- a/README.md
+++ b/README.md
@@ -49,6 +49,7 @@ A curated list of [free/libre](https://www.gnu.org/philosophy/free-sw.html) game
 - [Ringed](https://github.com/KOBUGE-Incubator/ringed) - Top-down shooter with extensive usage of light effects (Godot 2.1).
 - [Tanks of Freedom](https://github.com/w84death/Tanks-of-Freedom) - Free turn-based isometric strategy game (Godot 2.1).
 - [Three Hungry Mice](https://github.com/delstuff/threeHungryMice) - Breakout game with mice made for the Godot Engine Jam of March 2016 (Godot 2.1).
+- [TuxBuilder](https://github.com/Alzter/TuxBuilder) - Work-in-progress reimplementation of SuperTux (Godot 3.1).
 
 ### 3D