Square Enix have debuted a new online service, called Core Online, which will allow you to play high-definition games in your browser for free. No installation required. You can access the service here. It supports Cloud saves.
Games currently listed on Core Online include: Hitman: Blood Money and Mini Ninjas, with Lara Croft and the Guardian of Light scheduled for October, and Tomb Raider: Underworld and Gyromancer heading to the service “soon”.
The Core Online technology is developed by a company named Hapti Co. in Denmark. The Core Online service is supported by ads. Clicking on them will allow you to keep playing for free. Or you can choose to skip ads by purchasing the level (or game).