Publisher Square Enix has launched a surprise new browser-based games service at CoreOnline.com, offering up free versions of some of their legacy titles supported by earning game-time by watching user-selected adverts.

Both Hitman: Blood Money and Mini Ninjas are playable straight away for free, with Lara Croft: Guardian of Light, Tombraider: Underworld, Gyromancer and other Square Enix titles to follow soon, and an FAQ page explains the nuances of the ad supported system, which is currently completely free (but "possibly not always" as they test the waters) and claims players get approximately 20 minutes of game time for each 1 minute advertisement viewed.

We’re very keen to experiment with different business models as we work with new platforms and technologies. We’ve watched with interest how games and other media are monetised elsewhere – TV, social networks, mobile devices – and understand the importance of cost to consumers today. We feel that right now some are more open to small investments of time (watching ads) rather than small investments of money (micro-transactions) and we want to offer the choice.

The service itself supports both Windows (Chrome, Firefox and Internet Explorer) and Mac (currently Chrome only), but while Mini Ninjas is available on each platform, Hitman appears to be PC only.