@Extremmefan: Amy has been part of this comic since issue #101 -- I find it odd that you'd bring up this question, eight years after the fact.
The character lineup was originally based on who would appear in S3&K, which explains Sonic, Tails, Knuckles, and Robotnik. I added Amy only because up until that point, only Sonic and Tails made regular appearances, and I felt it was good to add a third regular character. As for why Amy appears in her "modern" form when she would've still had her "classic" appearance in this point in time, it was a matter of personal preference. There are larger sprite sheets available for Amy in this style, and frankly I like this look better.
Ah, yes. Sandopolis Zone. I hated the pyramid stage. Stupid ghosts! I loved Flying Battery zone though. It had a great soundtrack and it was pretty fun.
Anyway, can Tails hold 2 people at the same time?