If a Lander gets away with a humanoid, the two merge into a Mutant, an insanely aggressive enemy that not only comes zooming to your location but likes to approach from above your ship, where it's hard for your horizontal lasers to hit. If all ten humanoids are killed or abducted the planet blows up, and all the Landers turn into Mutants in every level until the next multiple of 5, when the player's humanoid supply is replenished. If this happens, you might as well walk away from the machine unless you're already a Defender wizard, because you aren't going to survive.

GameFAQ's page on the game (yes, there is one).

Check it out, it plays like R. C. Pro-Am, but it's not a racing game! It has boss fights! It has a Gradius-style powerup system! It has an amazing variety of action! And it's bone-crushingly hard!

Why did this game tank in stores? Why was this, which takes everything Rare's hit R. C. Pro-Am had and improves it off the charts, doomed to fail? The only reason I can come up with is that it's an incredible challenge, a game for experts.

Yes, Cobra Triangle is a game that demands mastery. Nothing less will do. Despite that energy bar at the bottom of the screen a depressing number of things will cause instant death.

This is where the fact that, when you push the stick, you move the level, not the ball, comes into play. If you think about it, tilting the level means moving it around a pivot point. The ball’s location is that point!

This one’s a bit challenging to get information on, since there hasn’t been a lot said about it since its release on the N64, the first game by then-hopeful startup Zed Two.

If the player digs a horizontal tunnel the whole length of the scrolling, wrap-around map, he’ll discover that the tunnel will be off vertically by one character cell when he gets back to the start, an artifact of the way the game stores the map in memory and handles wrap-around.

For some reason European developers, like Rare and Zed Two, seem less afraid of making games difficult.

A gigantic exploration game released two years before Metroid, containing fruit-shaped monsters, diabolical traps, and a heaping helping of mystery.

Some players these days consider a game only completed once everything has been unlocked; these games stand in direct opposition to that by offering rewards less than one player in ten thousand will see. It's worth noting that, for all these games, the mega goal is a complete secret: there is nothing in the game's UI to hint it's there until the player either achieves it or has a reasonable chance to. That way, it is a nice surprise for players who become surpassingly good, or at the very least, know how to read FAQs. (That's how come I know of the above things, by the way.)

The original Legend of Zelda is a game that has fallen out of favor in some circles, with many people claiming it's too primitive, too simplistic, or too abstract. Hogwash; what they really hate about it is that it's hard, dating from an age when video games were supposed to be tests of skill, and thus difficult.

And while most people can make it through the main game, the amount of the ending the player got to see depended on how many Gold Gems the player had found.

The secret spell ZZGO, a.k.a. “The Dreamspell” is not technically a cheat because it’s code is available in the game, but it’s not in the manual. It’s a multifunction spell that does incredible damage in combat and heals the party completely, and when used outside of combat allows the group to teleport to any dungeon.

Each of the seven main dungeons ends with a special area called a Death Snare. These are special puzzle areas set to a clock... a real-time one. Most of them would be fairly challenging on their own, but having to solve them to a real-world time requirement pushes them into frustrating, especially since teleportation doesn't usually work there. If the time runs out (and no clock actually appears on-screen) all your party members die, which is itself is quite a penalty to overcome.