I remember playing this split screen with my brother on the Playstation 1 as a kid, we got past the submarine level only to get stuck at the tank level for months, trying to figure out how to drive forward.
We'd just go in circles over and over, and we felt so proud when we figured out that you can alternate L1 and R1 to creep forward. Took us another week to figure out you need to hold them both to move forward (we were just little kids).
This game really did have it all (at least from the perspective of akid), aircraft missions, submarine missions, motorbikes, jeeps, tanks. It was janky as all hell and looked like a mid 90s game, but you could tell the team behind it had fun with it through the easter eggs.