this one: SnakeRattle N'Roll (nes + megadrive)
You play as Rattle or Roll (a red or blue snake), and run around in these 3D isometric levels, collecting these balls? (best to match the colours to the snake colours), to grow until you can ring a bell, that then opens up a path out, leading to the next level.
(nes version above, not as good looking as the megadrive one)
^ mega drive version.
Anyways the music was crazy good for its time, and it was fun platforming around as a snake.
Still have my copy on the attic somewhere (NES).
Superb game but I’ve never finished it. I always got to one of the ice levels (9 or 10?) and could never clear it, insanley difficult. Maybe I should fire up my NES and give it a spin again, it’s at least 20 years since I last played it.