A few really interesting ideas in here. Snake with conveyor belts could be a whole game. Trying to solve a maze with the snake mechanics was also interesting but I think with how random the apples spawn it didn't work as well since a lot of the time apples would spawn in completed rooms so you'd have to backtrack for no reward (and risk dying). And Predator mode was super useful but seemed necessary as controlling the snake without it seemed extremely difficult.
Best attempt got to a size of 42 but didn't find anything other than the normal apples. I had another few goes after reading about how the green walls are destroyed but couldn't beat that length or find anything new. On one run I just explored to the right and got the map to be five tiles wide and it wasn't the edge, how big is the map?