Puella Magi Madoka Magica Portable/WMG

Homura will discover that Ultimate Madoka is the best possible ending.
In the game; Homura will be able to jump from Pre-Anime to Post-Anime timelines upon "unlocking" them, and even if she's able to save all of the cast and beat Walpurgisnacht, the very nature of Puella Magi/Witches means they don't have long to live anyways. Even if she does so and prevents Madoka from becoming a Magical Girl; Madoka will tell her she doesn't want to be alone when they eventually die/go witch in a few short years.
 * Her final ending will be like Halo: Reach, her fighting an infinite amount of spawning Manjuu Demons in the Wasteland until she dies or ascends; and then goes to be with Ultimate Madoka.