Why not ship it media mail? The place I work uses it all the time, and it takes 4-6 days. 3 pounds will set you back $3.20 or so.
Postal code prohibits the shipping of games via media mail:
Media mail is used for certain types of books, films, manuscripts, printed music, printed test materials, sound recordings, play scripts, printed educational charts, loose-leaf pages and their binders consisting of medical information, video recordings, educational reference charts, and computer-readable media. Video games, whether on CD-ROM, diskettes, or similar software, or playable systems including computers, do not meet the standards for Media Mail.
And parcel post is both slower and potentially more expensive than priority.
The USPS site quotes priority around 2-3 days. The boxes should ship on or slightly before release, so you should have them no later than the end of next week if you're in the US. International shipping times will vary.