Beat Back the Horde

Several side-by-side screen images from Beat Back the Horde, showing red and blue triangles and circles fighting each other with some lines and particle effects.


A unique "rhythm-time strategy game" for Android in which players tap and drag to create units and walls to the beat of the music, attacking their opponent's base while defending their own. Playable in both single and multiplayer (by Bluetooth), the game is simple to learn but fun for hours! It is free and open-source software.

Research Topics

Game Engines | Flocking | Game Design


Evan Wallace | Justin Ardini | Tala Huhe | Zach Davis | Kayle Gishen


Beat Back the Horde centers around a unique game mechanic, which we term "rhythm-time strategy." Players must tap and drag on the screen to the beat of a song, placing units and walls to maximize their offense and defense. If they successfully keep the beat, they can complete combos to create Über units! A clear, effective tutorial provides an easy learning curve for new players, and the AI supports highly controllable difficulty. For a further challenge, players can compete against each other over Bluetooth.

The units are all AI-controlled, using a flocking algorithm (Reynolds 1987) to cohesively move towards and attack the enemy's units and base. Nonetheless, placing units and walls appropriately to maximize their effectiveness requires quick decision-making. Units deal area-of-effect damage, so clustering too many in one place is less effective, but leaving an area too sparsely guarded could leave your base vulnerable!

Built in a custom game engine for Android, originally as part of an "Android Game Engines" class at Brown University, the game's simple but attractive geometric graphical style, intuitive but addictive gameplay, and free, open-source, low-spec-friendly release brought it a 4-star rating and over 10,000 downloads on the Google Play Store for Android.


Released, Dormant


Reynolds, Craig W. 1987. “Flocks, Herds and Schools: A Distributed Behavioral Model.” In Proceedings of the 14th Annual Conference on Computer Graphics and Interactive Techniques, 25–34. SIGGRAPH ’87. New York, NY, USA: ACM.