CoverThe cover is reminiscent of the cover of the original WarCraft, which most modern RTS games base rules and gameplay on.
Extra campaignDue to many people complaining that Ensemble Studios never really completed the story of Brokk and Eitri (the two dwarven brothers who appeared briefly but poignantly in the single-player campaign of the original Age of Mythology), a new campaign was released by Ensemble called "The Two Brothers" which continues the story. It didn't actually ship with The Titans Expansion Pack, instead it was uploaded to the Age of Mythology Heaven downloads section, and can still be found there.
You can also find this campaign on Microsoft Download Center by the name The Golden Gift. This four-scenario campaign follows the brothers' first encounter with the god Loki and features all-new voice acting by the original actors.
Information also contributed by MegaMegaMan