Gold Rush is a very unique level. Although it uses the same "Old West" theme from "Smokey and the Bandicoot", this time, you get to travel through this level almost completely on foot, barring the mine cart and hang bars later on.
It's the longest level in the whole game, and with 209 Crates to smash open, that's not only the largest amount of crates in this level, but also the largest amount of crates in ANY level of the entire Crash Bandicoot series. This all sums up to why it's one of my favorites.
This level has the final colored gem, the Yellow Gem, which is very clever considering the level's name and theme. You know the drill: Go through its Skull Route first, die before hitting the exit, then respawn back at the main route to get the Crystal and eventually the normal Gem from there.
Very nice Western-styled music, too, might I add.