I've really never cared one iota for speed running. As much as I like the thrill of going fast in Sonic games, it's never my goal to get to the end of the level as quickly as possible. A lot of the time, I care more about the natural ebb and flow of speed variation, something you get brilliantly from the harmony between the level design and physics in the Classics, and to a lesser/different extent from the Adventure games, Heroes and '06. It's largely lost in the Boost games and feels much more artificial in both Lost World and Generations/Forces Classic Sonic. Going for a score attack is so much more fun than a time attack simply because you interact with the levels more. That's somewhere that SA2 and its ranking system really stand out, because they challenge you to actually play and engage with the levels whilst simultaneously going fast, rather than to do your best to cut out as much as possible. And further more, those interactions tend to be really gratifying. Of all of the 3D boost games, Unleashed manages it best, probably due to the level length. It doesn't measure up to the Rush series though. That's probably why I like the Classics and Adventures so much. I really enjoy getting the absolute most out of the levels. Especially when the levels get longer as in S3K, you really get a enjoyable rhythm and balance that encourages you to get a taste of everything on offer. Level skips are laaaaaaaaame and that's why I can't get into speed running (Sonic or otherwise). Do I want to perfect my routing and get the best time? No way. I just want to go with the flow, and unintentionally end up taking different routes on subsequent playthroughs. The Adventures are much more linear than the Classics, but they have their share of diversions. They're tuned for linear experiences that have variable pacing with a variety of interactions.