Why the hell did Chris de-age when he went through the "portal" anyway, apart from it being artistically convenient?
It's said that while six years passed in Chris's universe, only six months had passed in Sonic's. I suppose the de-aging was just a result of Chris technically only being six months older in Sonic's universe.
Which makes even less sense since several months had supposedly passed by the time Sonic had made his way to back to their world (which was all of a day after his friends had teleported back), unless his journey really took that amount of time rather than due to space and time complications. Earth supposedly has the slower time continum in the first season finale, then is suddenly several times faster than Sonic's world the start of the second season.
There's a theory in the Wild Mass Guessing page that it's the Master Emerald's fault - he passed through it to get to Sonic's world, which could mean that the portal was just reconfiguring him when he got to the other side as the Master Emerald itself "remembered" him being.
One thing that bugs me about the last episode is why earth didn't Sonic try to comfort Tails, God Tails just lost the love of his life, did Sonic hate her or something
Of course he didn't hate her. Were we even watching the same episode? It's just that he's SONIC. He's just not the type of person who knows how to deal with emotional situations and grief. Some people just don't handle grief by being openly tactile and apologetic. He didn't hug Tails back because he was basically didn't know what to do and it might seem obvious to us that the answer is "hug the damn guy" that doesn't mean it's obvious to Sonic - all he could think of to do was say sorry for not finding her. He clearly WAS sad and sorry you could see it in his face.
What he should have done (i.e. what we feel would be the right thing to do) and what the character would do are not the same thing. This is actually pretty typical behavior for X Sonic: His earlier response to leaving a friend forever was "hey, let's go for a run", and he can never accept Amy's advances for various reasons, but jumps into water to save her and still wore the present she gave him. As said above -he's Sonic. He's not the kind of character, in this continuity anyway, who deals with emotional situations by hugging and telling people it'll be okay.
The anime's interpretation of Sonic was generally given a more limited and one dimensional personality compared to other depictions, likely due to playing something of The Ace in the show. SEGA had in fact already taken action against other medias making Sonic too emotional a character, suggesting they don't find it part of his character to break his dignity, even if it makes him somewhat cold at times such as these (granted even the games Sonic was more openly sorrowful at times, case in point Elise's Disney Death).
Exactly. In the japanese version Tails was yelling "I believed in you! I BELIEVED IN YOU!" in reference to Sonic unable to save Cosmo. It would have been a hypocritical move for Sonic to hug Tails like that, since he was half of the reason his buddy was crying in the first place.
A minor addition - the series was written in Japan. The Japanese are a lot more conservative with their emotions than Americans. Once again, this is one of those things that loses something due to culture clashes and translations. Of course Sonic cared. But it would have been rude, in Japan, for him to start drawing attention to his friend's distress in public. Especially since Tails was upset at him as well.
I have one more query about the Metarex saga, why in the heck did they bring Rouge and The Chaotix along, i mean why not bring along Big? the only real impact that Rouge and the Chaotix had was helping Amy Finding out Dark Oak's identity and helping out the people on the human planet for Rouge as for the Chaotix, the only impact they had was Shipping Tails and Cosmo together.
How the hell was sending Sonic and his friends back to their world saving both Earth and (presumably named) Mobius from merging together when clearly not only was Eggman from Earth (so it was suggested after discovering his grandfather's notes) and spent most if not all his life on Mobius but the Space Colony ARK had been hovering above Earth since its creation, being manned by Gerald Robotnik? Was the merging of the planet so slow that it just needed that one extra push of colourful characters?
Related to the above question, why did Chris look to teleport to Sonic's world considering the massive risk of the obvious convenient plot point of merging worlds could be made into a reality once more? Is the kid just OUT to cause an apocalypse because of his own selfishness?
Well, he has had a few years to work out a safer method of doing it and is now inexplicably a genius, or something so maybe it's possible. Portals are probably more reliable than huge, mad fluxes of chaos energy and a lot easier to reverse if you realize you've screwed up. And one can argue he always intended to go home again -remember it took months, if not longer, for the time-flux problems that required everyone to go home again to start happening, there was no reason for him to assume the world would explode the moment he stepped into the portal. Kid just needed some closure, I guess.