Played through Tekkaman Blade [Super Famicom].
I love a good shoot-em-up / platformer hybrid (Wonder Boy III, Xexyz, Robocco Wars), but Tekkaman Blade is the first shoot-em-up / fighting game hybrid that I've ever played. And in spite of my general distaste for the 1-on-1 fighter genre, I had a lot of fun with this title. I liked the consistency in stage partitioning, where progression felt predictable with just enough small variations to keep things interesting and imply that you're advancing through a broader "quest". The layouts and enemy patterns were admittedly clunky, and the slash-mechanic never felt quite as reliable as in action-games like Ninja Gaiden, but my expectations were more or less tempered for that, based on Tekkaman Blade's relative obscurity (it never even saw a release outside of Japan, although that isn't necessarily indicative of low-quality).
I'd be remiss not to attribute most of my zeal for this game to the aesthetics, though. The moment I saw a 16-bit mech with a lightsaber, my brain automatically filed Tekkaman Blade under "greatest things ever" - right next to vanilla wafers, vacuum cleaners, and Godzilla. Apparently this game was based on an early-90s anime of the same name, and I'd like to watch it some time - but I have an irrational bias against anime that I still need to get past before I dive into anything like that.