What are some alternatives?
When comparing Galaxy on Fire and OGame, you can also consider the following products
EVE Online - Player-created empires, player-driven markets, and endless ways to embark on your personal sci-fi adventure.
Vendetta Online - The space-based MMO Vendetta Online balances an online trading system with tense ship-to=ship combat.
Evochron Mercenary - Official Webpage for Evochron Mercenary, a 3D space combat and trader simulation. Screenshots, free demo, forum, cheats, videos, and more.
StarMade - StarMade is a Minecraft inspired 3D space shooter.
Empyrion - Empyrion is a 3D open world, space survival adventure in which you can fly across space and land on...
ScrumbleShip - ScrumbleShip is the most accurate space combat simulation devised to date.