Update

Sonic Last Gen was changed to work with midis instead of mp3s (less space required with midis), but the GMK (game maker project) file was lost to corruption, so the game continues to use MP3s for music. Here's the things updated in beta 8 (unreleased)

• Redesigned bossfights: Robotnik no longer gives a warning before shooting, and doesnt stop when hit, but you can get hit by the missile as long as you are jumping and not die.
• Less glitchy Knuckles: In the last version of Sonic Last Gen, Knuckles' punch move was kinda glitchy and strange (what happened was a "fist" appeared out of him while he just stood there). Now, his pose changes while punching, he moves forward while punching (like sonic advance), and his punch makes a sound.
• New Graphics for Knuckles: Since I didn't really like the Knuckles sprites from Knuckles' Chaotix (32X), I replaced them with the sprites from Sonic 3/Sonic and Knuckles. These graphics fit better, and more actions are available that are not available with Knuckles' Chaotix Knuckles sprites (i.e. punching and dying).
• Spindash and Roll Attack Added: One of the worst things about Sonic Last Gen was the not being able to roll or spindash. Well, now that problem is solved. Spindashing and rolling work just like the original games: press down while in motion to roll, and press down and X to charge up your spindash.
• New Sound Effects: The sound effects for Sonic's homing attack, jumping and Amy's double jump, and a few others have been changed.
  
• New/Changed Music: Some music tracks have been changed, like Bridge Zone, which is now the original 8-bit version of the Bridge Zone music, options screen (which is now Sonic 3 time attack screen music), and special stage music (sonic 3 "get blue spheres" music). A new track has been added: the music from the extras screen of Sonic Mega Collection (GC/PS2).
• Secret Level Select (you didn't read this): There is now a secret level select that lets you select every single level in the game so far, even the secret levels not accessible in normal gameplay. To get to the level you need to play 4 sounds on the options screen (hint: it has something to do with sonic 1 on the genesis/megadrive, but thats all im saying).
• New Zone - Spring Alley: A new zone, based on the original Spring Yard Zone from Sonic 1 was added to the game. This level features a lot of springs and other things.