You've arrived at the last level of the island, but to go to the second, you must climb the Native Fortress. - Level description
Native Fortress (とりでの てっぺんへ lit. Towards the Top of Fortress in Japanese) is the ninth level (including boss fights) and is the final level (third-to-last in Beta) of the first out of three islands in the original Crash Bandicoot, as well as the second and last stage set in the Native village. This acts as the way out of Papu Papu's stronghold and is considered by most players to be much harder than the previous "native" level and the hardest level on the island.
This level features a secret area, required to get all the crates in this level. Said area is notable for its structure, as it's only made of a few, thin clouds that Crash can walk on, as well as for being the best way to see this environment's beautiful background: a view of the other two islands, seen at sunset. Crash will need the red gem from Slippery Climb (or The Lost City in the Japanese version).
Translation of Aku Aku Hints in the Japanese Version
Sometimes you think that you have broken all the boxes, but you still don't get perfect. That's because the disappearing color diamonds have secrets. If you have got the green one from Hog Dash, got to the jungle.
Note that in the Japanese version, the Green Gem lies in the level Hog Wild.
At the red gem part of the level, when on the clouds, the player can see the other two islands; Wumpa Island and Cortex Island.
In the prototype, there is no red gem. The path that requires the red gem is not there.
The prototype does not have the first 2 checkpoints present in the retail version, making it harder.