It sounds like you're talking about Gauntlet Dark Legacy. I also remember guides about how to leave levels with more health than you entered them (there were ways to regain health). It's hard to single this series out as "a total ripoff" among all kinds of arcade games designed to extract quarters out of you. You can't expect someone to stay on a screen or backtrack forever. Some games use a timer, some throw an endless amount of mobs at you. The nature of the game (which was built in part around exploration) was that they used the health amount as HP + timer.