Will the retail version be activated via Steam or does it have an independent EA activation?

The Steam and retail versions both use SecuROM product activation online.

Will the Steam version have an activation limit?

The Steam version of Crysis Warhead has the same activation limit as the retail version of 5 activations. The Steam version of Crysis Wars will only require authentication upon installation just like the retail product.

How often can I install the game which I got from Steam?

Re-authentication is required only if you make significant changes to your PC's hardware, reformat your hard drive, or in some cases, upgrade your Operating System. Multiple installations of the game on the same computer that has not gone through significant changes will not count against the number of computers the game can be installed on.

Does Crysis Wars have online activation?

Crysis Wars is authenticated upon installation. If you want to play through Gamespy Arcade, you’ll need a valid registration key like most online games that use that service.

Can I play online only via Steam?

Online play for all versions of Crysis Warhead is done through Gamespy.

Are Crysis and Warhead the same when being downloaded via Steam as the hard copy ones?

Yes, the binaries and content are identical.