Game preservation is a tricky process at the best of times, but it's even more challenging when the games you're talking about are tied to a defunct platform and were only ever made available for purchase digitally.
That's the task that faces the many hard-working people who are trying to preserve games which were released for Japanese "feature phones" (or "keitai") back in the days before smartphones took over.
Because keitai culture was so massive in Japan, some of the game industry's biggest publishers supported these devices with exclusive games – many of which are now considered lost media, as there's no way of downloading them as the networks associated with these unique devices have long since ceased to exist.
The only way to preserve such games is to find phones in the wild which have them pre-installed, and @YuviApp has just saved nine such titles from being lost forever.
Of particular note are Devil May Cry: Deadshot and two exclusive RPGs, Your Planet and Hajimari no Doukutsu.
Some of the games are ports, such as Rockman X and Area 88, and while they're not quite up to the quality of the original games, they remain interesting from a historical perspective.
Without the hard work of the community, these titles would be lost forever.