The versions of Seaside Hill, Sea Gate, and Rail Canyon that can be found in the E3 2003 prototype have been updated and sound more or less identical to the final by this point. There are numerous songs in this build that have differences to their final counterparts, from subtle to obvious.
A lot of the sound effects are jittery.
This dream project is a massive combination of the first two Sonic titles and also incorporates many aspects from Sonic 3, Sonic & Knuckles, and Knuckles’ Chaotix. For one, Metal Sonic's voice isn't filtered. Sonic Classic Heroes was initially started as Sonic 2 Heroes by flamewing until community suggestions prompted the developer to collaborate with fellow romhacker ColinC10. On the team select screen, the characters' positions are off and they are in different poses.
Oddly, some characters in the background appear twice.
