I'll forgive you if you've forgotten about Bethesda's Commander Keen reboot. Announced at E3 last summer, the mobile game didn't exactly garner much goodwill - and now it appears to have disappeared entirely.
As spotted by Twitter user Nitomatta (via VG247) the game's web page redirects to the Bethesda website, and there's no mention of Commander Keen either there or on the Zenimax page. The game's Twitter account is locked, and official trailers appear to have been made private. A Google Play page still exists, but the game isn't available for download.
Bethesda hasn't made any announcement, so it's difficult to be sure whether or not they've actually cancelled development of the game, or whether this is some kind of reboot. Nevertheless, it's not great news for a game that didn't exactly get off to the best start - a mobile version of a classic franchise seemed like a bold move right from the beginning, and it doesn't appear to have garnered any extra popularity since then.