Game of skill with falling blocks

Julius is an open source re-implementation of Caesar III

A re-implementation of Jazz Jackrabbit 2

A spider puzzle game!

Old school multiplayer RPG

Match tiles and clear the board

Fun with Blocks

A 3D open-source kart racing game

The Free and Fast Arena Shooter

A sliding-puzzle game

Real-time strategy game

Tomato smashing game

A simple GOG client for Linux

Viper is a launcher and updater for Northstar, and not much more than that

Fast arcade first person shooter

"Five in a row" board game

Fast, faithful Classic DOOM action — solo or online

Lunar Lander style arcade game

2D game engine for visual novels

Multiplayer vector graphics space game

Multi-platform Scorched Earth clone similar to the Worms series of games

Manage your racing team

Old cellphone arcade recreation

Gtk+-3.22 based client for the Freeciv game

Expand your own Roman Empire!

Roguelike RPG, with pixel art graphics and lots of variety and replayability

Source port for Build engine games

Cosmic horror first-person shooter

Brogue: Community Edition - a community-lead fork of the much-loved minimalist roguelike game

Fan project that reimplements The Settlers 2 game