The SEGA Master System's Zaxxon 3D, a console exclusive, was the games first true sequel (Super Zaxxon was more of an upgrade to the original game) and featured a full soundtrack of exciting music. (segabits.com)
Finally, the first true sequel to the retrotastic (real word that one) Bionic Commando for the Xbox 360 and PS3. (thatvideogameblog.com)
Meanwhile, the «first true sequel» to arcade classic Galaga was also shown off. (mcvuk.com)