Turrican II: The Final Fight AGA (Public Domain)

Turrican II can be described as a cross between Metroid and Psycho-Nics Oscar. While the huge detailed labyrinth levels and the morph-ball function were inspired by Metroid, the overall graphics design and weapons were inspired by Psycho-Nics Oscar.

The game is divided into five distinct "worlds", split across eleven levels, each with its own themed music provided by Chris Huelsbeck, plus a final showdown with the boss known as "The Machine". There is a music menu accessible by pressing the Space-Bar (Amiga version), where all the in-game music is available to be listened to. The music to Turrican II is widely regarded as one of Huelsbeck's best compositions, and it was performed live by an orchestra at the second Symphonic Game Music Concert in 2004. In 2016 Chris Huelsbeck created a limited Collector's Edition Box Set featuring new live orchestra recordings of music from Turrican II.

The game is played twice: Normal mode with the original sprite, and Hard mode with the PC sprite.
Can be downloaded for free here: https://sonicslothgames.itch.io/turrican2aga