The 2014 video game Middle-earth: Shadow of Mordor takes place between the events of The Hobbit and The Lord of the Rings. In it, an undead Gondorian Ranger named Talion is bound to Celebrimbor's wraith by the will of the Black Hand of Sauron.

What I want to know is, are there any inconsistencies with the timelines, characters, etc. (Was there really a guard of Men at the Black Gate, and was it attacked? Could Celebrimbor actually have come back as a wraith? Is Gollum's appearance justified? etc.)?