User blog comment:Aftenshnoshnikr/Attack On Titan's Tribute Game/@comment-11227880-20140524094917

just to clear up some stuff, Feng cant really implement certain and many aspects of the anime/manga because as it stands, its an unofficial tribute game and some Devs can be mean and take down fan-made productions even if it is not-for-profit, if Feng were to recreate many more maps, characters, boss fights and scenes from the manga unavailable in the anime, the developer would have more reason to take down the game, on copyright grounds or not, because it features their anime/manga and they love making money.

if Feng were to create a storyline/campaign, canon or not, the developers have more than enough reason to take down a game that presents the story of Eren, without having to pay to watch the anime/buy the manga series.

So Feng has to be extra careful with his work, things like campaigns, larger maps, graphics design and more bosses take much, much more time than just adding a singleplayer map. It takes teams, professional designers/programmers to implement things like that, and with the budget and literal two-man-army that he has, its tough enough fixing bugs and making sure levels run smoothly.