Cloud-based gaming service Gaikai has finally entered public beta testing, CEO David Perry has revealed on his blog. Five games can now be played direct from your browser, including the previously un-demoed PC edition of Dead Space 2.

Requiring no plugins beyond Flash and Java, Gaikai renders games remotely on distributed servers then streams the game back to your computer as streaming video. While input is somewhat lagged and visual quality is understandably lower than it'd be on a top-notch PC--look right for snaps from my own experiences--games are quite playable and will run on relatively low-spec hardware.

Unlike similar service OnLive, which is a full-fledged digital distributor, Gaikai is focused on offering demos to help advertise games, and doesn't actually sell any itself. As well as developers and publishers, the company's looking to connect with retailers and gaming sites.

A demo for Mass Effect 2 can be found on the main Gaikai site, appearing through a pop-up if your connection is up to scratch. The Dead Space 2 demo is accessed through a survey. A 60-minute trial of The Sims 3 is here. Spore can be played here. Second Life is this-a-way.

Gaikai's network is currently live in 12 countries across 24 data centers. Perry notes that "Our goal is to end up with data centers in every major city in the world peered directly to the key internet service providers in that area."

Although Gaikai might not help with one important function demos serve for PC gamers--testing a game's performance on their system--being able to easily play a game's demo in its website will surely prove attractive to many players, no matter what platform they'll ultimately buy it for.