Update: SEGA got in contact with us today with an updated statement on the situation:

Due to the expiry of music rights in Alpha Protocol, the title has been removed from Steam and is no longer on sale.

The original story is below, with minor updates regarding the situation. We are following up for more information and will update as more becomes available.

Alpha Protocol was Obsidian Entertainment's first game that didn't draw from an already established IP after their first two titles, which were both sequels to BioWare games, Star Wars Knights of the Old Republic II: The Sith Lords, and Neverwinter Nights 2. However, SEGA still held the rights, and though Obsidian had an interest in developing a sequel, SEGA never greenlit it on account of the game's poor commercial performance at launch. Now, as it approaches its tenth anniversary, Alpha Protocol is no longer available for sale from Steam, PlayStation Store, or Xbox Marketplace, as noted by Resetera users.

The Steam page specifically says "At the request of the publisher, Alpha Protocol™ is no longer available for sale on Steam", while on other storefronts there's no mention of it having been available to purchase.

As we noted in our feature on the 15th anniversary of Obsidian Entertainment, Alpha Protocol had a complicated development history and a complicated launch. It was and remains a niche title as a spy RPG. When Obsidian first pitched it to SEGA, it was well-received. According to Obsidian CEO Feargus Urquhart, “[SEGA] loved it. They said, ‘Hey, this is different. It’s not dragons, it’s not phasers.’ You don’t see a lot of spy RPGs. Sometimes we go: maybe there’s a reason for that!”

The final product, as released in 2010, was rather underwhelming and overshadowed by BioWare’s Mass Effect franchise, which had a similar dialogue wheel system—at the time a novel design. Apart from that, it was lacking in terms of gameplay, graphics, and AI, all the while suffering from all the usual problems that Obsidian’s games had suffered at launch. The writing and its handling of choices and consequences were very original and the game achieved a certain cult status mostly because of it, but that wasn’t enough for SEGA, who announced there would be no sequel.

We've reached out to SEGA, Microsoft, and Obsidian Entertainment for comment on the delisting of the game. SEGA has responded with the following statement:

Following the expiry of SEGA’s publishing rights for Alpha Protocol, the title has been removed from Steam and is no longer on sale. It’s also worth noting that any customers who have bought and downloaded Alpha Protocol will still be able to play it and any customers who have bought it but not downloaded it, or since deleted it will still be able to download it at any time, so it doesn’t change anything for the owners of the game.

We will update this article if more information becomes available.