Silent J’s review published on Letterboxd :
Christian Bale really amazes me. Not because of his acting talent, but how he can just constantly lose and gain weight day in day out. He's so skinny it's scary in The Machinist, then he's buffed out for Batman Begins and The Dark Knight, then he basically looks like a crackhead in this film and then bulks right back up for The Dark Knight Rises. It's un-friggin-believable.
Christian Bale does a fantastic job (probably not his most Oscar worthy turn though) but while everyone says he steals the show, I think Mark Whalberg proved just why this is his show. He displays the right levels of emotion at the right times, he's captivating, stood out the most despite such a strong cast, and is so excellent that he gives what should have been an Oscar worthy performance. You also get terrific supporting turns from Amy Adams and especially Melissa Leo. The story is strong and powerful. The boxing scenes are pretty solid in my book. Great soundtrack. Just a solid biopic that really showcases how terrific it's cast is.