Sonics Secrets: Herzog Zwei.
Use the following code to play the final stage: JLJOIGBAOLH
These codes activate other maps:
GGGKHAGOKLO
NPLOFOCAGKP
JAJJBPDNCMC
JLJOMGJAOKL
LHJKINAFAMA
BPHOHACAGML
IMLPFEGEMLC
LILOPBDPIKJ
JLJOIGJBOKO