Sonic the Fighters

I would just use fang. His gun can keep the other fight at bay and also get 3 shots if your lucky, only draw back is when your opponent blocks with barriers the gun doesn't work well then but if they are close enough just kicking works too

For this achievement you'll need to complete Stage 5 of Arcade Mode.

For the Arcade Mode of Stage 5 you'll be facing against Tails. If you want an easy going match you can choose Easy mode, with attack power +3, and only 1 barrier so you can easily overpower your opponent for an easy win.

Once you've defeated Tails you'll earn this 20G achievement.

The following video will depict this solution.