As mentioned on the cardboard sleeve the box contains a bonus Master Chief avatar costume and a ‘Grunt Funeral Skull’ game modifier that makes the grunts explode like a plasma grenade when activated.
Not only this, but there’s also a DLC code inside for Halo: Reach containing 6 classic maps, a new Firefight mission and a 2 day gold pass.
A quick look online reveals that only Play mentions these goodies, which are being offered as a pre-order incentive. Our copy wasn’t pre-ordered though – we obtained it early as somebody at certain supermarket (Tesco) accidentally put copies out earlier today.
This should mean that everybody who purchases the first batch of copies will get the bonus DLC. There’s no reason that shouldn’t be the case, at least.