DotEmu is described as 'offers DRM-free classic PC games like Raptor, Moto Racer, Gobliiins, Broken Sword, Commandos and more classic retro games for cheap'. There are more than 10 alternatives to DotEmu for a variety of platforms, including Online / Web-based, Windows, Mac, Linux and iPad. The best alternative is Steam, which is free. Other great apps like DotEmu are GOG.com (Free), Instant Gaming (Free), G2A (Free) and GamersGate (Paid).
G2A is an online marketplace (akin to eBay) for video games on a wide variety of platforms such as Steam, uPlay, Origin, Xbox and PlayStation. Both G2A and community members sell a wide variety of games on G2A, at prices which tend to be significantly less then standard prices.
FreeToGame is a gaming platform that provides access to the best free-to-play games and MMO Games while rewarding gamers with free premium in-game loot, special offers and exclusive perks at no cost to the user!
Marketplace to buy/sell game keys for a myriad of platforms including: Battle.net, EA Origin, Free2Play, GOG.COM, NCSoft, Nintendo, PlayStation 3, PlayStation 4, PlayStation Vita, Steam, Uplay, XBOX 360, XBOX ONE, and others.