User blog comment:JAlbor/Dishonored Interview Opportunity/@comment-1824113-20121002030817/@comment-5561656-20121004012458

Raf has said there were 20 powers that made it to certain stages of production and five-seven were cut at various points. Others were blended into a power that made it into the game, i.e. Agility is Agility, Celerity and Feather all rolled into one.

One power we know of came from the Reddit interview. Harvey described a power in consideration where you could turn into a two-dimensional shadow. Ultimately, they realized it was such an in-depth power that the focus required was enough that it would require the attention and grab the spotlight akin to Blink.

That said, I'd like to know any other "babies that had to be killed" also :)