Ultracore

The game was planned for release in 1994 and it was almost ready, but its release was canceled and it was called Hardcore. In 2019, a German company finished the game and released it on multiple platforms. The game is visually reminiscent of Contra-HK, but it's essentially more of a metroidvania. Through the levels you have to search for bosses, keys, and maps. There are level passwords available.