Some pre-order bonuses have appeared on the official website for Batman: Arkham City today.

GameStop and Best Buy are offering different perks to customers who pre-order with their particular retailer. GameStop customers will get the "Joker's Carnival" challenge map and those who choose Best Buy will receive a unique combo pack.

The deals for Batman: Arkham City are currently only available to US customers, but we're sure similar deals will follow for other countries around the world before Arkham City's highly-anticipated release later this year. No further details of the extras have been revealed yet, but the combo pack is likely to be a unique set of moves that players can use in-game to tackle enemies.

Retailer-specific perks tend to annoy some - especially if the participating stores are out of reach. While in many cases the same content will still become available for download from the PlayStation Store/Xbox Live marketplace at a later date - it will likely come at an additional cost, leaving some players with a sour taste in their mouths.

That said, any sour taste is likely to be washed away by the quality of Batman: Arkham City - considering the more details that emerge, the better the game looks. From the super-slick trailer to new details about the Riddler's increased involvement in the Arkham City story, it's hard to believe that gamers still have over six months to wait for the title to arrive.

All the signs are looking good for Arkham City. So far, it appears to be shaping up as a more than capable successor to the fantastic Arkham Asylum - despite not having the addition of multiplayer, a feature many had hoped for in the Rocksteady Studios title. The inclusion of some great characters such as Two Face and Hugo Strange, and the larger, more open world feel to Arkham City looks to provide a good example of why multiplayer is not entirely necessary in all games.

Which Batman: Arkham City pre-order bonus will you pick? Do you think it's fair to have retailer-specific content? Let us know in the comments.