Well, hopefully I can make you feel a bit better about this fight. It's qute simple to me, Kratos didn't fight back. He let Deimos win. The story did not make it obvious, but to me there were hints that Kratos did not want to really fight his brother and that he kind of related to the rage that Deimos was feeling at the moment. Yes, it is silly that Deimos' power would even rival Kratos', and more silly that Thanatos would arm Deimos with a gauntlet when he's supposed to be a prisoner, but the fight itself seemed to me that Kratos was holding back. When Deimons had Kratos pinned to the ground, Kratos did nothing before getting pummeled into the ground. Even the trophy unlocked at that time right before Thanatos interferes was called "Let Him Win". Besides, Kratos proved he was the greater warrior by saving Deimos and then beating Thanatos on his own. And if Kratos was as angry fighting Deimos as he was when Thanatos killed his brother, Deimos wouldn't have had a prayer.
I actually really like Ghost of Sparta, despite the fact that I'm not crazy about the brother story either. I'm not even a fan of seeing child Kratos, but the style and imagery was my favorite of the series in fact. I thought the game had the perfect balance of puzzles, platforming, and action. Most of the dialogue was good with memorable lines and moments from Kratos (Is this all a game to you Athena? The gods will pay for this), although some if it was brutally forced (I will not lose you again...Deimos!). I liked seeing Kratos treat his fellow Spartans honorably, and loved seeing him return to Sparta, which I thought was just masterfully done well. The boss fights were cool and the spear and shield were a very nice addition to the gameplay. And although I did not like seeing Kratos' story as a child, I thought it was awesome when Kratos confronted his inner self and bashed his child self through the mirror. Had it just been about a game about Kratos' quest to find the secrets from his mother that would have worked, but Deimos is a lame addition to the story and him being "the other one" just made him feel like the Princess Leia to Kratos' Luke Skywalker.
Overall, I felt it was a nice bridge inbetween the two original games. My biggest beefs with it though are that Deimos actually becomes a canon character, and that considering he is in his full god state, Kratos isn't any more powerful in this game than he is in the others. They really missed some opportunities to have Kratos majestically come from the sky like Ares, destroy Atlantis as a giant, or use some insane powers that he should now have at his disposal. I was disappointed there that he didn't even get too creative when killing Thanatos. He just attacked him like he was still a regular mortal...except with fire blades.
