Ludicrous in-game explanations for normal in-game mechanics

But some games can't let it go. They feel the need to justify things that don't need justifying. They go out of their way to "plausibly" explain why you can't go over into that area just outside the map, or why you can't spam that uber-weapon quite as much as you'd like to, or why the level is laid out the way it is. The more extravagant the attempt at believability, the sillier it gets, until eventually things go so far that someone writes a feature about the whole phenomenon. That someone is us and that feature is this one.

• In an attempt to pass off its massively linear city-based environments as a living, breathing open world, the new Bionic Commando fills them with clouds of radioactive gas. Gas which coincidentally always borders the route the game wants you to take. It seems there is no wind in Ascension City.
• Wander too far into Far Cry 2's outer desert and heat exaustion will kick in, forcing you to return to the main map. Strangely, only the desert near the limits of the map has this effect. Presumably the proximity of mission objectives lowers the ambient temperature elsewhere.
• Crysis' ocean doesn't have invisible walls. It has a very visible shark. And he just loves the taste of nanosuits.
• Earthbound limits your path with police roadblocks. The reason there are so many? The PD is trying to break the world record for setting them, naturally.
• Yet another reason to hate mimes. In Family Guy, you can meet one who has used his "art" to create an actual, real invisible wall.

• The Legacy of Kain series explains away the lethality of water by simply making it a (rather crap) supernatural property of its vampires. Which raises the issue that a water-soluble race of walking corpses who fundamentally can't wash must absolutely reek.
• Command %26amp; Conquer: Red Alert's Soviets deliberately don't train their troops to swim, in order to minimise desertions. Because a drowned soldier is loads more useful than one who has simply run away.
• Psychonauts has some fun with this old platforming cliche. It's explained early on that Raz's family are the victims of a lethal water curse, meaning that they'll die if they go near it. But rather than drowning like Mario or Sonic, going for a paddle will see Raz instantly beaten senseless by a large tentacle. Made of water.

• Why are alien worlds in Metroid games almost always constructed out of obstacles tailor-made for Samus' suit's abilities? Easy. The planets are usually of Chozo origin, as is the Power Suit. And if they're not, then they're the worlds of races who've stolen Chozo tech. Given the proliferation of Morph Ball pipes throughout the galaxy, the Chozo really should have looked into patenting.
• Similarly, the ever-changing, massively inconvenient layout of the castle in Castlevania is explained in Symphony of the Night by the building being a living creature of chaos. And we thought Drac had just really pissed off his architect.
• Does Burnout's Paradise City seem just a little too conveniently filled with jumps and ramps? Apparently it's the fault of a lazy City Works dept. Lazy is one thing, but those guys seem positively trained never to finish a job.
• The Mars base in Doom might be laid out in a way which would make day-to-day operation a ludicrous undertaking, but that's only because Hell's encroachment has twisted it out of shape. Satan just loves his keycard puzzles, it seems.
• Some of the floating platforms in the Metroid series are justified by the addition of small jet boosters. Because jet boosters turn fantastical videogame staples into hard science.