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.
The first one was so awesome, it made it into I Wanna Be the Guy as the theme for the Final Tower of the Guy, continuing on for The Guy's first form!
Breather Boss: King Bee is considered MUCH easier than the previous two bosses and the following boss.
Demonic Spiders: Many enemies can be this, but the Tyrannosaurus and Allosaurus are the worst of the bunch, being able to cause massive damage very quickly, and also being nearly unbeatable if you're not tall enough.
Goddamned Bats: Trilobites in the Fish Age chapter, most flying enemies if you're not a bird, and the monkeys and dino-people in the final chapter.
Hell Is That Noise: When you beat Bolbox, a very, very odd noise is repeated over and over. Considering how hard the fight was, this is a rare occasion where the noise is also the Most Wonderful Sound.
Moment Of Awesome: It would be a cop out to say the whole damn thing, but evolving to the strongest possible level and absolutely curb-stomping that one enemy you could never defeat before? Just great.
The moment you finally beat Bolbox. He moans repeatedly and slowly fades out of existence, with you screaming in joy at what was probably the hardest boss in the game.
It Was His Sled: The Final Boss is a monstrous cell with an awesome battle theme. Thanks to I Wanna Be The Guy, this song is the first thing related to the game some newer players learn.
Nightmare Fuel: Bolbox can be this sometimes. The level with the cockroaches borders on it as well. As for the Queen Bee's face... ouch.
Older Than They Think: The SNES game itself is HEAVILY based on a much older game by Almanic called 46 Okunen Monogatari: The Shinka Ron ("4.6 Billion Year Story: The Theory of Evolution"), released only in Japan in 1990 on a very obscure home computer called the PC-9801. E.V.O might even be considered a heavily-downgraded port, which is odd because as we all know, the SNES can handlesome pretty epicRPGs.
Signature Scene: The final battle with Bolbox. Mainly because of how bizarre the entire scenario is, the awesome music, and the brutal difficulty. In fact, thanks to I Wanna Be the Guy, this might be the first part of the game one learns about.
Tear Jerker: The death of the father amphibian and the extinction of the dinosaurs are surprisingly heartbreaking.
The same could be said when the son of the yetis in the Ice Age finds that his father and mother are dead by your fault. It's somewhat shocking by the survival of the fittest thing.
The scene where all the meteors crash down on the planet's surface, ushering in a new age results in ALL THE DINOSAURS BEING BEATEN TO DEATH. The worst part is at the very end where the camera stops panning over all the dinosaurs that you have been fighting only to focus on the ONE DINOSAUR that asked you for help. And what do you see? The mother styracosaurus curled up around her baby that you had saved, trying in vain to keep it alive. Fade to black...
Which of the three yetis? The father yeti is somewhat problematic, but the mother and the son's descendant are the most problematic ones, especially the son's descendant, when you have to fight with him in the last segment of the game.
The giant outside Bolbox's cave, the shark at the beginning and the Cockroach of Bolbox. The bosses in this game are abnormally difficult.
You may have a horrific time with the queen bee, even using cheat codes to stay alive.
Bird Man King is not afraid to utterly destroy you, being a threat even as the dragon. If you die, you need to do That One Level all over.
Mt. Brave is partly this trope and Brutal Bonus Level (it's optional). Birds pick you up and force you to start over. And the reward you get... is becoming a new class of evolutions, forcing you to start over. Unless you figure out how the Cloud Maze and River of Asteroids work, which give you the REAL reward: The Dragon and Gargoyle forms, along with a ton of Evo Points.