Alright, this is the first ramble I'm doing, so this'll probably be... messy.
This ramble is about the stage Rooftup Run Act 2 from Sonic Generations, which is one of my favourites out of Modern Sonic's stages. Whenever I boot up Sonic Generations I will usually play this stage and I've got decently good at it.
So first a summary of the level design. The act starts the same as in the original version of this stage, but with a cooler animation and some genuinely really cool scenery.
Neat. I believe the foreign text on the KEEP OUT sign is even correct. I like how you can see the clock tower from here, a setpiece that comes up later on. Anyway, the stage continues mimicking Unleashed by taking you through a hallway made of houses until you reach a rail to grind where if you jump of it correctly you can reach a Rainbow Ring. This is where the stage starts doing its own thing though, as instead of the Rainbow Ring being a bonus for you to earn some points, it will instead serve as a shortcut reducing a fairly long section of climbing stairs and attacking robots to doing some tricks. If you take this route, you can jump again for another Rainbow Ring shortcut, sending you into this decently spacious area.
If you take the shortcut at the beginning, you'll reach this point right as the music kicks in. I really enjoy stuff like that, where music syncs with gameplay. Anyway, you'll want to hit a spring, then homing attack some balloons while avoiding blades if you don't want the slower route. These are well placed here, because at least with the skills I use, getting the optimal cycle with these blades is really tight and feels great. Taking the slower route does take you to an area resembling Professor Pickle's lab, a good reference to not RTR but Spagonia itself, the setting of the stage. Anyway, after taking the high path, you'll find some blades. You could try waiting to get between them but you should realise you can just slide. Then, a quickstepping section with the spikes in the original stage, but this time something is throwing them at you instead of them just... appearing. Once that's done, do a couple jumps to avoid a slow pulley. Soon after is the first 2D section, starting with the high route reached by doing some wall jumps while avoiding a blade. I like how these keep getting expanded on throughout the level, they make you play quite carefully. Soon after, some usage of Four-Way Cannons, which seem to be the Generations friendly version of QTE Cannons from Unleashed, because uhh, QTEs bad. After this you RUN UP THE CLOCK TOWER. In Unleashed it was quite an effort to climb it but now you just effortlessly go up it (well there are some robots attacking you but still) 2D section again! I like the scenery here, it's quite unique.