Some of the final levels, especially the “??” level unlocked once the previous 99 were complete, were a right pain. Many were of the form of huge swathes of blocks and baddies, where removing them in the right order so others drop down in certain ways, which I find difficult as it’s hard to visualise how the level will look three, four, or 27 moves in the future. Levels where you generally just have to find a way of reaching a couple of baddies, or getting a block from A to B are far easier to plan.
But I managed it eventually, and verily, the game was won. My reward? I got to play the new Sonic Generations demo on the 360. And that is a story for another post.