It doesn't have to. You sometimes need to explore just so you can finish the game. This whole thread is coming from the perspective of seasoned players, which tends to be the case in Sonic discussion boards. Back when I first played Sonic CD, I didn't know there was such thing as a good ending. I just wanted to finish the game and I liked going to the bad future better than going to the past simply because the past has more enemies, is sometimes more complex to navigate and I'm sure all hazards work. In the bad future, some badniks are broken and I simply may not find as many obstacles, given the same path (EDIT: except for Tidal Tempest, which is super cruel on bad future). So if I died nonstop, either in the present or in the past, I'd simply go to the bad future to make the game easier -- but that required me to explore. That, or consider how you'll sometimes just... wind up in a different time, and that'll make you reconsider everything about the stage you're in there and then. It adds depth to the game from a survival standpoint, which it should it it's your first time playing. Being careless may get you somewhere you just don't know, and so the game will keep you on your toes. And that's very important, I think, because it made Sonic CD not just worth playing a second time, but also made it completely different once I learned I could, and I should, find and break all transporters. Yet, it was the same game. EDIT: also, from what standpoint would Sonic CD even need to use its time periods evenly anyway?