Play open source games
A freeware game is a game you can play completely for free with no payments needed: no microtransactions, no subscription fees.

OpenTTD
simulation / management
OpenTTD Team

Cataclysm: Dark Days Ahead
RPG / roguelike
Kevin Granade

Unknown Horizons
simulation / city building
The Unknown Horizons Developers

Battle for Wesnoth
strategy / turn-based tactics
David White

0 A.D.
strategy / real-time strategy
Wildfire Games

Angband
RPG / roguelike
Angband Development Team

Dungeon Crawl Stone Soup
RPG / roguelike
DCSS Devteam

Hurrican
platformer / run and gun
Poke53280

FreeCol
strategy / 4X
The Freecol Team

Alien Arena
shooter / first-person shooter
COR Entertainment

TomeNET
RPG / roguelike
TomeNET team

Warsow
shooter / first-person shooter
Warsow Team

Widelands
strategy / real-time strategy
Widelands Development Team

Mirror Magic
puzzle
Artsoft Entertainment

OpenRCT2
simulation / management
OpenRCT2 team

Dungeon Craft
RPG / old school RPG
Dungeon Craft Team

OpenClonk
platformer
OpenClonk team

Simutrans
simulation / management
Simutrans Development Team

Xonotic
shooter / first-person shooter
Team Xonotic

Sextris
puzzle / tile-matching
Sextris

TORCS
simulation / racing
TORCS Team