I thought that I should give some of my tips for Jungle Cruise. I hope they're useful!
1) Do not speed up your boat, it causes fuel to run out very quickly, even if you're out of film, it will shorten your game by a lot.
2) To get flawless, take the picture of the animal quickly, and make sure it's centered.
3) On levels that appear to be going downwards (Elephant Bathing Pool, Explorer Tent, and Forbidden temple) the arrow keys are vice versa, so if you push the "->" arrow, you will go the opposite way.
4) If you are playing to get keys, here's the quickest way to qualify: The amount of points doesn't matter. But be sure to at least reach the Boat Dock the 2nd time.
5) In the Explorer Tent part of the game, there is a rock that is part of the scenery, not the game. But if you hit it, you will loose fuel. It is very easy to hit, so don't think that you can just run over it, since it's not one of the other rocks.
6) If you are running out of film on the 3rd time going around, just don't take a picture of parrots or toucans. They give very few points and it's better to save film to get high-pointed animals.
7) You can usually survive the first round without moving your boat, so just focus on taking pictures. Only do this if you are trying to win keys, and playing quickly. Just stay on a straight path and you will probably make it.
I hope this was useful!