Here is the full list of all 19 QUByte Classics - Radical Rex achievements worth 1,000 gamerscore.
Use the rex yo-yo (Portable)
Juggle (Portable)
Make the rex dance (Portable)
Take a ride with pyterodactyl (Portable)
Get 10.000 points (Portable)
Hop on the skate (Portable)
Beat the brachiosaurus machine (Portable)
Beat the pyterodactyl machine (Portable)
Beat the stegosaurus machine (Portable)
Beat the final boss (Portable)
Reach 99 eggs in one level (16-Bit)
Reach the max fire power (16-Bit)
Hop on the skate (16-Bit)
Beat the wizard mouse (16-Bit)
Beat the pyterodactyl (16-Bit)
Beat the bone stegosaurus (16-Bit)
Beat the disease (16-Bit)
Beat the wasp nest (16-Bit)
Beat the wizard mouse again (16-Bit)