These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Gameplay Derailment: Trying to grind some more lives on Turtle Woods? You think the moment when you fall into pit with cyberrats is annoying? Well, there is a legit way which, if doesn't work at first, is possible to pull off with some skill: just jump above the pit through the faux-walls. In fact, this trick was one of the many objects of this game's Tool Assisted Speedrun, kindly demonstrated here.
Same moment in Un-Bearable is also avoidable, but this time, with a simple slide jump.
Good Bad Bugs: A glitch involving the bonus areas in Hang Eight and Plant Food make getting their second gems, which involve speed-running through said levels, much more manageable.
Death-Warping. Once you collect a crystal or gem, it will remain in Crash's inventory as long as he remains in the level, even after he dies. Since extra lives are handed out like confetti, simply killing yourself the moment you get a gem from an alternate path seems far more appealing than backtracking manually.
To elaborate: Most levels in the game where you run towards the screen have you running from a boulder. However, in this level, you are chased by a large polar bear with a creepy grin...
Not to mention Diggin' It. That frightening buzz and the killer bees coming with their stings ready... it gets worse in Bee Having where a group of bees come together and only a well-timed spin can defeat them all, if you fail, the will get you.
The Game Over screen.
Scrappy Mechanic: So you decided to play it safe and avoided destroying crates next to nitros, thinking that you'll get them anyway once you trigger all of them to explode at the end of the level? Too bad, since that only affects the nitros. Time to start again.
To some players, the jetpack levels in the final warp room also count.
"Bee-Having". Grenade spitting plants, swarms of bees that chase you, and a TON of Nitro boxes make this an extremely tricky level to finish.
"Road to Ruin" and "Ruination" are also among the hardest in the game. Swiveling, tilted platforms, very narrow platforms, and monkeys that throw logs at you (though you can always spin the logs away). On top of that, there's one bit in Ruination where you find a helpful little ! crate, and a bunch of wire frame boxes ready to appear for you to destroy so you can get the gem! Smack the block, and...no wooden crates, just a field of Nitro Crates with barely any room to maneuver. Good luck!