Crisis Force is my favorite co-op vertical shooter on the Famicom. The production values were top shelf for its time. The number of innovations are really impressive- They include temporary super-weapon, selectable aim, end-stage bosses with multiple forms, minibosses of distinct sizes, small enemies flanking when you attack a cruiser, and a few more I surely forgot. I happen to very much dig the whole "Chariots of the Gods"-style aesthetic the array of monsters seem to embody.
I don't find Recca to be an enjoyable game outside of very small doses. Too unrelenting for my tastes. It gets monotonous after 20-30 minutes' worth of restarts. The music tracks might arguably be the most dynamic and realized of the trio in this poll, though.
Gun Nac is a competently made game, however I'd describe that one as a complete pushover, challenge-wise. Never found the cheesy rabbit-centric visual motif anything to write home about, either. It was one of the select few 1990s vertical STG's I beat on my first attempt, and with crazy surplus lives to spare. It's also one of several Compile games I have minimal interest in revisiting, but am glad to have played through in their entirety nonetheless.