Two years after being re-released on modern platforms, a beloved Marvel superhero video game and its sequel have been delisted from digital marketplaces. “Marvel: Ultimate Alliance” and “Marvel: Ultimate Alliance 2” were taken off virtual store shelves on Thursday, probably due to expiring licenses, according to Eurogamer.

Savvy posters on the popular video game forum ResetEra noticed the games, which were re-released on PC, PlayStation 4 and Xbox One in July 2016, had received steep discounts on Steam, the biggest digital marketplace for PC games. The heavy price reductions just a few days before the two-year anniversary of the games being re-released on the aforementioned platforms tipped off gamers that the licenses might be expiring.

Their worst fears came true on Thursday. Now, anyone who wants to buy “Marvel: Ultimate Alliance” and its sequel will need to track down physical copies.

Both games were “Diablo”-style action games with deep upgrade mechanics, with the biggest hook being huge rosters of Marvel superheroes. Players would build teams of four heroes and could play together with a four-player cooperative mode as they tried to take down a cavalcade of Marvel supervillains.

The first game was released in 2006 to fairly stellar reviews, while the 2009 sequel was not quite as beloved. Publisher Activision released remastered versions in July 2016, but those versions were criticized for technical problems upon release. Those versions also reportedly did not include promised downloadable content at launch.

As mentioned above, anyone with physical copies of the games should still be fine. They have been delisted from digital marketplaces, but can still be played.

Video games are removed from digital marketplaces somewhat frequently. Companies shut down and licenses expire, after all. A full list of delisted games can be found here. This has been a problem with Marvel games before, as a “Deadpool” game released in 2013 was actually delisted twice.

Video game preservation faces numerous challenges, as outlined in a 2016 Kotaku feature about the practice. As it becomes more popular for consumers to buy games digitally rather than on disc, it could become more difficult to keep games around thanks to delisting practices.

The "Marvel: Ultimate Alliance" video games were removed from digital marketplaces this week. In this photo illustration, vintage Spider-Man and X-Men Marvel comic books are seen at St. Mark's Comics on Aug. 31, 2009 in New York City. Mario Tama/Getty Images