yea,no one has mentioned it yet,but,if yal dont feel like looking back to the rulebook,this is the arena.

Flash Column - A 200 foot long cylindrical steel silo, about 75 feet in diameter. The column is filled with platforms, wall-mounted flame jets, shock pads, spiked walls, trap-doors and even more deadly devices. The entire structure is held on a giant hydraulic arm, and at three different stations on the inside, the position of the column can be manually switched from vertical to horizontal or diagonal. Each station can only be used once per battle.

Now,i think Zero has the advantage right here.If Zero can flip one of the switches to horizontal,sonic will have to run up the wall just to get to Zero,and if he stops for just a little bit,hes gonna fall.If u know Zer like i do,he can teleport to some places,some times,and he is able to jump/fly in the air temp.the only thing stoping zero is if either sonic flips another switch,or zero hits one of those shock pads or gets hit by the flames.I think Zero has it in the bag

"What you have feared has come to life.What you have thought was a nightmare,was certainly real.You will now feel the pain i felt!!!!"- Evil Kashante Megikekuu.