Upstream

Crash Bandicoot can't swim, but he needs to climb up the stream if he wants to beat Papu Papu. - Level description

Upstream is the fifth level of the first island in Crash Bandicoot. As the name implies, Crash must travel up along a stream, without falling in.

Level design
The level is extremely linear, and is bounded on both sides by the banks of the stream which are covered in dense jungle foliage and occasional small sections of temple ruins. Crash must navigate his way up the stream by means of logs, leaves, stone platforms, and sinking lily pads. He must also jump across several red plants with green stems (somewhat similar to venus fly traps) which will snap shut shortly after he jumps on them. There is also an alternate blue-stemmed variation of this plant, which snaps shut at regular intervals, requiring timing to get past it.

Gem
Before Crash can obtain the clear gem in this level, he'll first need to get the orange gem from Generator Room, a level that appears much later in the game. Once the orange gem has been obtained, Crash can access and break all fourteen crates.

Trivia

 * The river in this level rises at Skull Rock Waterfall.
 * The premise of Crash navigating up a stream is repeated later in this game in the level Up the Creek, and in Crash Bandicoot 2: Cortex Strikes Back in the levels Hang Eight, Air Crash, and Plant Food.