i was gonna do the hard extra levels, completed the first two and then watched someone else do the rest and was like...nah, i'm good. they're all unlocked from the start so there wasn't that same satisfying feeling of progression and achievement for me, though i might go back and do them later. the rest of the game, aside from a few obtuse moments, hit a sweet spot for me of challenging my brain without being headbashingly difficult....a very nice change of pace from smb 3 which i played before this. also, even though it's a fairly linear game those gorgeous backdrops and the frequent sense of scale really created a great sense of discovery and exploration