A partnership between Atari, Microsoft and Grant Skinner's team of developers at gskinner.com, the new versions of the games are optimized for touch and most of them include multiplayer options. The games are free to play, but unless you opt to use Internet Explorer, you will see ads - most of which disappear once you start playing. In any case, if you are a developer the advertising represents revenue and so is to be encouraged.
Promoting Internet Explorer, in particular touch-enabled IE 10, explains Microsoft's role in this partnership but IE isn't the most interesting component as far as developers are concerned. The Arcade menu includes a direct invitation to devs to build and publish games to expand the Atari Arcade. Enrolling as an Atari Developer is free and once your game is published you will:
begin to earn a competitive revenue share based on advertising, in game purchase, and other future revenue sources for your game.
The tools provided for developing HTML5 games for Atari Arcade are its SDK and CreateJS, an open source library that has the following components:
EaselJS: A library which manages sprites, animation, vector and bitmap drawing, and user interaction (including multi-touch) based on HTML5 Canvas. It uses a display list concept that mirrors that offered in Flash.
TweenJS: A simple and chainable tweening engine that transitions numeric or non-numeric values over time. It is optimized for use with EaselJS, or can be used on its own.
SoundJS: An audio playback engine, which allows pluggable modules to play sound using a variety of methods based on your users' capabilities.
PreloadJS: Takes the guesswork out of preloading your assets, whether they be images, video, sounds, JS, data, or whatever.
Zoë: Configure and export spritesheets from Flash animations, optimized for use with EaselJS.
As CreateJS is open source you can of course use it for any HTML5 game creation, and this account of how it was used for the Atari Arcade games is pretty inspiring.
Visit Atari Arcade if you want to play or develop games and for a taster here's the promo video:
One problem with Internet Explorer using games as a showcase for its talents is that as it doesn't support WebGL and offers no alternative 3D engine the games that can be created are of the "classic" Atari type. There is nothing wrong with classic games, or casual games which is what 2D games tend to be, but compared to the sort of 3D game demos that Mozilla and Google are producing they are unexciting and not as impressive.
When it comes to gaming, IE9 and IE10 are severely behind the times for reasons that have everything to do with Microsoft needing to protect its own technologies, i.e. DirectX.
All that this polished demo does is to make clear that IE isn't part of the modern web.