I have a huge soft spot for Capcom's Strider (Arcade, 1989) to the point that I have an actual PCB. Wildly ambitious in terms of design and worldbuilding...and incredibly janky. Also, it has a co-opted soviet council turn into a giant mecha-centipede wielding a hammer and sickle. Notably influential within Capcom's own devteams, having characters who influenced Street Fighter II's Chun-Li and Mega Man X's Vile.
Also fitting the bill more directly, we have Wolfteam's Earnest Evans (Sega Mega Drive/Mega CD, 1991). A lot of 16 bit games successfully played with segmented characters for an early form of skeletal animation - like a lot of well respected classics like Alien Soldier and Contra: Hard Corps - but Wolfteam tried to take things a step further with a entire platformer where the main character has sophisticated ragdoll physics. The end result isn't very playable, but it's pretty impressive for a platform that can't do hardware rotation effects. Also one of the all-time funniest speedruns imo.