I finished Sonic the Hedgehog 4: Episode I. I liked it, but I find that it feels way too much like a rehash of Sonic 1 and 2. The levels, bosses, and gimmicks all feel like they were lifted directly from those two games. In that sense, this doesn't feel like a true sequel. The game is also extremely short. Despite all that, though, I still enjoyed Sonic 4's first episode and recommend it if you're a fan of the classic Sonic games on the Sega Genesis or Mega Drive.