RAMPART. An Atari Games arcade game with strong strategy and puzzle elements. Very difficult in the arcade, and has like 12 home ports, including one as late as the PS3. A lot of Atari arcade games from that era aren't talked much about these days, but with Rampart it feels especially egregious.
I could mention lots of games here. I love lots of overlooked games. I even like Athena, of all things, and I am fully aware of its many flaws.