Remains one of the few NES games I could never beat.
Did I mention it was difficult, ridiculously so in fact, so hard that I never even saw or much less know what the final boss or boss level even looks like? If you were able to make it through to the underground volcano level, and if you were able to pass that utterly ridiculous jet bike race that required such quick movement only a speed texting champion on crystal meth can regularly accomplish, you were met with the challenge of climbing those mechanical snakes that always seemed to hang you out to dry when you were absolutely sure you knew their pattern….
…I may have only passed that snake level once, maybe.
Still though, that was the first game I ever remember breaking the fourth wall and giving you the enemies POV while you fought it. It also in my book marks one of the first times in my memory that the idea of "Team Killing" was put into a co-op playable video game (I am pretty sure you could do the same thing in DD2, but with Battle Toads you could deal much more damage and Big Boot your buddy right out of the game from the get go). It also was the first time the video game industry embraced the idea of cartoonish fighting character with cartoonish power moves.
This game was fairly innovative in its time, but again the extreme difficulty along with no save file or progress continuation, pass words and such that other games in the era employed was a real knock on the legacy of the title. Still it was fun, though unbearably frustrating. If you can find it in an emulator sit down with it for a while, and hope the programmer gave you the option of continuation via level select screens, cause damn, the game was difficult.