Uh, it actually does. Sonic 1 for the Android/iOS has several level sections edited and added for Tails and Knuckles to take. Off of the top of my head: Green Hill Zone 1 has an additional 10 rings above the lamp post in the middle of the 2 "S" tunnels. Marble Zone 1 has an additional invincibility monitor that has a custom level chunk made for it. Marble Zone 3 has a new path that skips the original underground path. It comes out right near the boss and is a little faster to take than the original. Spring Yard Zone 2 has an additional 10 ring and shield monitor near the start of the act on a really high platform. Spring Yard Zone 2 has a new path near the end of the act (a third signpost and level end) that has also hides an additional 1-up and ring monitor. Spring Yard Zone 3 has an additional 10 ring monitor on a platform just before, and above, the boss. Star Light Zone 1 has a new path right near the start that also holds a 10 ring and a speed shoes monitor. There might be more (I can't remember all that well), but it appears that quite a few additions were made. I like the fact that these additions make exploring with Tails and Knuckles all the more enjoyable.