Use the mouse for everything (left-click -> move around, right-click -> zoom or view additional text and links in card form). You may use keyboard arrows for walking, spacebar for jumping and alt for zoom or card view. TAB changes into fullscreen view. ESC at any time reveals a menu with OPTIONS related to game quality and hardware performance.
Mac or Windows computer with fast dual CPU, 2Gb memory and modern graphics card. Firefox or Chrome or Safari or any modern browser supporting Unity Web player plugin. Expect browser or plugin crashes if shared video memory. Expect also much better performance than anticipated if there is a fast video card with exclusive video memory. Nvidia will probably show the best performance. If browser crashes every time try another browser (Firefox and Safari seem to work).
Any Mac or Windows computer with i5 or i7 or faster CPU, more than 4Gb memory and Nvidia or ATI fast graphics cards with fast graphics memory. Use the OPTIONS menu after pressing ESC to tailor performance to your specific hardware.
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