The Shiptest Codebase
You can make it - Open Source MMORPG Platform
RTS game with the theme of Strategy by Design
FlightGear Flight Simulator: free open-source multiplatform flight sim
0 A.D. is a free, open-source, cross-platform real-time strategy game.
An elegant Go board and SGF editor for a more civilized age
An open source blooket auto-player / cheat
Bitburner Game
games for kids
Space shooter style game arcade version - Games/Entertainment Software
An online multiplayer real time strategy game
A question-answer game for various trivia topics for road-trips
Baystation's flavor of Space Station 13
Multiplayer online game using Phaser + WebSocket (Socket.IO)
The best code this side of the galaxy
Edition of football teams on HTML canvas- javascript source
Open source script based on Master XLS
Simple data driven web based gamebook engine using javascript.
Next generation web chess club
Built to be ease of use, with no programming knowledge, Multi-platform
A very basic browser based adventure game.