What did Diablo's creator change when he made a Marvel game?

Every change on this page is traced to David Brevik's own words in interviews given while he was building the game, between 2012 and 2013. Where a claim about his design rests only on later summaries, this page says so and leaves it out of the verdict.

The deepest change was identity. Diablo asked you to build a character from a handful of classes. Marvel Heroes handed you Marvel's catalogue instead. Brevik, in March 2013: you can think of each hero as "its own character class, very similar to how I've made games in the past." Diablo II had started with five classes, then seven. "This is the same thing, only this time we are starting with over 20." Customisation moved inside the hero: power trees, builds, and costumes decided which Wolverine yours was, a point he made at New York Comic Con in 2012, where choosing a costume could also choose a specialisation, his example being an X-Force Wolverine built around bleeds.

The second change was scale. "Diablo games have been very insular," Brevik said in 2012. "There's been a strong hub and spoke model." Marvel Heroes replaced the small private game with shared public zones, central hubs, and public events built to pull crowds of heroes together. As he put it in the same period: "We're taking Diablo 2 to the next level. We're taking an action RPG and we're turning it into an MMO."

The third change was the business model itself, and it shaped the design. Diablo was a box you bought. Marvel Heroes was free, funded by a shop. At New York Comic Con in 2012 Brevik was blunt: "It's totally free," with microtransaction shops selling things that have "very little impact on gameplay," and no option to buy power. Preview interviews from the same period record the same rule in his words, "we're not going to sell power," and his stated model was League of Legends: be generous, let players unlock heroes by playing, and let costumes carry the revenue.