Clive Howlitzer said:
Usually yes, you can be sued by a celebrity if you blatantly use their likeness for advertising or money making purposes (like if you took a photo of them without their permission and used it to sell beer). One of the reasons is that it's defamation of character, you're saying "this person drinks beer" even if that person has a strict personal code against drinking alcohol.
That being said, for entertainment works (like books, movies and assumingly video games), it's a case by case basis, because these works are also protected by the first amendment. If it's a blatant use with no other creative merits, (like if you took a picture of a celebrity and plopped it on a T-shirt, to sell the shirt), yes you can be sued. I believe though that this falls into the other case...
As a general matter, you will not be held liable for using someone's name or likeness in a creative, entertaining, or artistic work that is transformative, meaning that you add some substantial creative element over and above the mere depiction of the person. In other words, the First Amendment ordinarily protects you if you use someone's name or likeness to create something new that is recognizably your own, rather than something that just evokes and exploits the person's identity.
Personally I hope she lets it go, but the case would be very interesting if Ellen Page does decide to sue, because the law isn't really clear specifically for video games. Games have gotten so advanced that we can run into these issues now. I imagine though that they'd treat it similar to how they treat these cases in films.
More info here
http://www.dmlp.org/legal-guide/using-name-or-likeness-another
Artists do use references of celebrities pretty often as a basis for making characters. Sometimes it's even completely accidental where a person drawing that character might have seen Ellen Page and so that's just an unintentional mental image they recall when they think of a character named Ellie. Artists and writers can't usually just pull completely original concepts and characters out of thin air, it's why websites like TV Tropes exist.
I did a concept for an elvish character once and to get away from the elvish influence (because I didn't want people taking one look and saying "oh look an elf"), I added cat features. Then Avatar came out and I saw the Navi and went "Damn those look a lot like my cat elvs, except giant and blue."
I also created a creature based off of Cerberus and when Harry Potter came out, everyone started calling my creature "Fluffy". My creature wasn't based off of Fluffy, I didn't rip a creature from J.K Rowling, but rather both Fluffy and my creature were based off the same source, Cerberus.
