This short article is in need of work. You can help NEC Retro by adding to it.
Energy (エナジー) is a vaguely Metroidvania style action game. While it does require the player to go back and forth across the map to go to places they couldn't before with new items, there's very little that can be done out of order. The many amateurish flaws of this game, such as the fact that bosses can keep firing at you for several seconds after you killed them, that locked doors pop up long after they should have and disappear in a similarly delayed time, and that the screen by screen, Zelda like scrolling is bizarrely slow have caused this game to have a reputation of one of the worst games on the PC Engine platform. An English fan translation patch exists that also speeds up the scrolling to a tolerable speed, though one has to wonder why they'd try to improve a game that's mostly notable for being bad.