Its hard to imagine any Sonic fan playing as the main antagonist of the Sonic the Hedgehog series, but this hack shows that it is possible. A lot of changes have been made to the game in comparison to Sonic in Sonic 1 in order to allow Dr. Eggman to play for as long as possible, so he will not be able to collect any rings, open monitors or get killed by any enemies. He can, however, lose a life in the game, by getting squashed, landing on a spike or falling. Interestingly, when he does lose a life, the game freezes, so the game has to be reset each time Eggman dies. He can run and jump the same speed and height respectively as Sonic. Some aspects of the game will mean that Eggman will not be able to complete some levels. Instead, in order to play him in every level, it requires the level select cheat to be activated. Special stages are also not possible in the main game since Eggman cannot collect rings, but these stages can be accessed via the level select cheat, although Sonic is the character that competes on that occasion. Overall the hack is pretty difficult and frustrating, since losing a life means you cannot continue to play without resetting the game, and that the full game cannot be completed from start to finish. 

The game is plain and is not a professional hack, that's for sure. :/ but they did it. Your review summed up the game well, good job.