There’s got to be a story of some kind behind that.
I always thought the asteroids universe was toroidal. What else could it be?
A stale rice cake is reward enough for beating a level . . . if you’re lucky, you may get to play rock/paper/scisors with a giant bad guy, who will vanish upon loosing.
When you’re near death from multiple bullet wounds, a turkey dinner that’s been left on the floor will fix you right up. Dog food’s a lifesaver, too.
A poorly-maintained lawn will totally kill a Smurf.
An essential part of fast-food burger assembly is having a little man walk all over the component parts. (Most people know this intuitively.)
Shooting tanks of your enemies fuel is a good way to refuel your fighter in flight.
The corpses of creatures you find in subterranean rooms can be preserved indefinitely by shooting more arrows at them.
Smart bombs really are pretty smart.
Walking over the rivets that hold girders together has a serious impact on a structure’s integrity. You should do it anyway.
A really big water drop from a leaky pipe is a common hazard for stunt pilots.
The best way to keep centipedes out of your garden is with a mobile heavy laser.
Metal Gear Solid 2
When speaking among themselves, Russian (?) terrorists use English.
Being shot in both hands is instantly fatal to enemy soldiers. Maybe their horror at being forced to blasphemously re-enact the Crucifiction is so great that they keel over from self-inflicted heart attacks.
It is possible to maintain a mind-bending ten-minute conversation with a pair of deranged AIs when fighting a man clad in an armoured tentacle suit and swinging a pair of swords at you while running around and leaving trails of fire all over the place. Isn’t that handy to know?
Rubber suits protect against cold, guns and missiles, but take double damage from fire.
Rubber suits also function as Bags Of Infinite Holding.
Final Fantasy (and assorted RPGs)
The first time you meet the Big Bad, s/he will not burn your low-level ass into random molecules despite being about as powerful as the time you finally fight him or her and despite his or her desire to get rid of you.
Real warriors celebrate victory by jumping up and down in unison.
It take approximately five minutes to cross a continent on foot.
Your characters will happily steal everything of value from a complete stranger’s home, but they’re all far too polite to ask somebody to stop standing in the damned doorway.
The intimidation factor of a Big Bad is inversely proportional to his or her actual effectiveness as a villain.
The most common result of a boxing match, and frequently the ONLY result, is the three-knockdown TKO. A 10-count, no matter how big a mismatch it is, is a truly rare event. “Decisions”, of course, are bizarre nebulous things that never happen in real life.
The face wrestler is alwasy some generic no-talent wimp whose moves are much, much less effective than those of even the wimpiest heel. Furthermore, he can NEVER duck or release a hold, something every heel can do at will.
If you’re driving at upwards of 180 miles and hour and crash, one of two things will happen. Either your car erupts into a fiery explosion before instantly rematerializing in perfect condition, or it does a spectacular series of flips and/or spins before returning to the center of the road in perfect condition.
Your bullets are always a helluva lot faster than theirs and usually have better range.
A “ninja” is a solider with crappy weapons and the toughness of a paper towel. Although he sometimes get a few lame acrobatic tricks or a super attack he can do one friggin’ time to compensate.
If the hero isn’t a warrior or else someone you’d expect to hold his own in a fight, his preferred attack is invariably jumping on top of the enemy, which is very deadly. (If he is a warrior, this attack is extraordinarily ineffectual, at best stunning the foe for about half a second.)
Your airplane can take one bullet…one…before blowing up. Thankfully, this is also true of most enemy aircraft.
Nobody can hit 3-pointers worth a damn. Anyone who shoots better than 10% from behind the line is a videogame Reggie Miller.
All of the evil mastermind’s flunkies can be dropped with one punch. The exceptions are the really tough ones that require TWO punches.
Will have specific examples in a bit. 
However, if you’re playing metal gear solid, a robotic ninja will be able to swing his swords at amazing speeds to block as many as 13 9mm rounds every second, so you have to go up and start punching him to death.
First aid kits will heal anything instantly. There are no specific anatomocal wounds, there are only life bars which can be restored with no permant effects whatever.
In Max Payne, painkillers can heal bullet wounds.
Along the same lines, Clubber Lang will always defeat Rocky Balboa if he can manage to stand slightly to the right of him.
Various RTS games:
An area of land can be attacked with nuclear weapons as many times as ou like, it will have no lasting effect on the environment. Feel free to station your troops there.
Once a ship or boat of any kind has its HP reduced to 0, it is lost forever. There are no such thing as shipwrecks. Furthermore, ever member of the crew will go down with it.
No member of your army will ever question your orders. Futile deaths are embraced.
Pereferably after the radiation dies down, in about 30 seconds.
Actually, in total annilation, I believe that there is some debris left behind by the destruction of an enemy vehicle.
If your strength is insufficient to use a given suit of armor, just put it in your backpack and carry it around until you’re strong enough to put it on. This works with swords, guns, and other items requiring a given strength value to use, as well.
All ductwork contains at least one headcrab.
Undead police officers not only have infinite ammunition, but their pistols have near-infinite range and accuracy. Your pistol does not, despite the fact that you got it from an undead police officer. (They Hunger)
In Warcraft II, burning farms still produce resources. For that matter, they will never actually burn down unless orcs come and beat on them with bladed weapons.
Oh, I totally forgot about Wasteland. Anyone remember this one?
Anyway, there’s only a limited amount of gear you can carry on your person. But, if you go through the radioactive zone, and your buddy dies, you can carry the same amount of gear on his dead body and drag it around. It’s way more practical than just carrying the gear around.
Just trust me.
If, at any time, you find a room packed to the rafters with health packs, weapons, ammunition, armor, and other handy stuff you’ve been needing for quite some time now,
(a) you are about to get hit in the head, captured, and stripped of all your stuff, or
(b) you are about to encounter an extremely nasty Boss Critter of some sort.
If a particular household does not subscribe to your newspaper, you are allowed to vandalize their house with rolled up newspapers. No charge.
If you don’t skate fast enough, the bees will find you.
Our princess is in another castle.
Red mushrooms make you grow, and green ones give you 1UP, but the red ones with black spots WILL kill you. (Japanese original Super Mario II)
A typical military aircraft can carry between 80 and 100 heat-seeking missiles, plus a couple dozen AMRAAMs on the side, and unlimited machine gun ammo that you will never need.
Monsters come out of houses placed in corners of the dungeons. Big houses produce big monsters, but if you hit the house and make it smaller, the size of the monster is also reduced.
The dagger that you have at the beginning is more powerful than the lightsaber you have at the end. (one of the old Ultimas)
Things I’ve learned from Metroid:
*No matter how kickass your weapon, there are just some bits of infrastructure that you can’t destroy no matter what. This is very reassuring, because you don’t ever have to worry about accidentally collapsing the tunnel you’re in with a Super Bomb.
*You can curl into a ball less than 1/4 your size, roll with perfect control, drop up to five bombs that materialize out of nowhere, jump, and even stick onto walls sometimes.
*Metroids, once they latch on to you, do not come off.
*If it moves, shoot it. If it doesn’t, bomb it.
*In game maps are your best friend.
*You can survive deep space, acid, and boiling lava in nothing but a sexy bikini.
*Never assume anybody is gone for good. Not even planets, for that matter.
*Samus is the only competent bounty hunter in the entire universe.
Things I’ve learned from the Legend of Zelda games:
*With very few exceptions, Hylians can’t jump.
*It’s probably due to the fact that your tunic is ungodly short and you’d flash everybody in sight if your feet ever left the ground.
*Time travel doesn’t ever cause paradoxes, even when it should.
*Everybody assumes you’re an idiot, because they keep asking if you understood them, and even your companion fairy feels the need to explain what the hell a Stalfos is every single time you run into one.
*It takes exactly two minutes to run from the Lakeside Laboratory to the top of Death Mountain, and that’s if you do everything right.
*Carrots mysteriously regenerate themselves when you’re on horseback.
*Tall grass hides money, arrows, and even bombs.
*Despite only having one male every 100 years, the Gerudo managed to remain an ethnically and culturally distinct peoples.
*Evil energy can be deflected by the Bug Catching Net.
*Your inner self is a bunny. With sharp biting teeth, one assumes.
*You never know when you’ll run into someone who has an interest in an otherwise completely useless trinket.
*No one can endure the sight of the Great Fairy because she is ucking fugly.
Things I’ve learned from Megaman games:
*In the future, the height of fashion is titanium underwear.
*Weapon energy never lasts as long as you need it to stay alive.
*When you die, your nuclear-powered core goes critical and you explode. (This is actually in the MMX game manual, I think.)
*For an evil genius, your opponent sure has no creativity when it comes to plots to take over the world.
*Once you’ve gotten a taste of the wall climb, it’s really hard to go back.
*Your closest friends have a penchant for nobly sacrificing themselves…over and over again…
*Continuity means nothing, as long as people will still buy your games.
Things I’ve learned from Konami Games:
*Up, up, down, down, left, right, left, right, B, A, B, A, select, start.
No matter how many times you kill 'em, the damn space invaders keep attacking.
Not only that, earth has only a single car with a gun pointed skyward that can only drive backwards and forwards to repel them.
Apparently Congress got a little too happy with the defense budget cuts.