"The levels that take place during the day recall Sonic's glory days, when the little blue furball zipped around the screen so fast that the player's greatest challenge was simply anticipating what came next and deciding whether Sonic ought to stay his course, slow down, or perhaps jump. They switch seamlessly between a rear perspective, which allows players to control Sonic's movement from left to right as he avoids various gaps and spiky perils, and a side angle that feels a lot like the perspective of Sonic games of old -- had the hedgehog been moving through them at five times the pace. It's fun, habit-forming stuff.
Unfortunately, the game drags when Sonic changes form at night. His alter ego is capable of doing pretty much the same basic things that game characters have been doing in platform games for ages, such as climbing posts, shimmying along precipices, and smacking around hordes of bad guys then collecting the bits of energy they leave behind. It's not that these traditional platform levels have been badly designed, but rather that they bring nothing new to the table. There will be times when players wish the game was composed solely of the speedier missions."