telltale signs of an upcoming boss battle

[Time Travelling Toaster]

When you see something huge darting down the corridor.
A blood curdling scream that your characters run to.
When whatever your on in the dungeon/base/whatever stops dead.

 

[One Seven One]

you walk into a big, empty, round room (first one that came to mind was the first boss in majora's mask)

very decorative door (most games that have dungeons)

and falling down a giant hole in the floor (legend of zelda majora's mask - fish boss)

 

[hannarr]

You see a brief cutscene shwoing the boss doing something, i.e. running around the stage, dropping in from the ceiling, ect.

Zeldaaaa!!

 

[maddawg IAJI]

In Gears Of War right before the Corpser fight you can easily see it trying to get at you. Hell for the last 2 chapters it's been tearing up the terrain toying with you.

In Left 4 Dead the tank always shows up when there is a strange lack in zombies unless you have been recently boomered. (Unless your me in which case it shows up as soon as I leave the safe room.)

 

[snaaaake]

1. There's the standard coming to the exit of a cave or forest.
2. An area has a giant pool of water or something like it.
3. Somewhere pretty so it can distract you (The Pain in MGS3).

 

[Calobi]

Just a door of some sort. Typically it's rather large and ornate, but not always. There will be a room on the other side, but it'll look like no one is in it, or there will be a single person. Anyone forming a ring around the lone person or the center do not count as being there as they will serve no real challenge.

 

[Mr. Fister]

In side-scrollers, you can usually tell when a boss is coming up if you go into a room with no platforms in the air and nothing happens when you walk forward a few feet. Or if the door leading into the boss room is large and red.

 

[aww yea]

when you can kinda see the boss in the distance

also a

"we're going here to kill this guy" motive kinda warns of an upcoming boss

especially if you just reached the last room in a place

 

[Fraught]

1. the game starts spoon feeding you ammo and powerups out of nowhere in a safe area

2. a save spot right next to a giant door -_-

These two pretty much.

 

[meece]

the level becomes empty of enemies for a bit...y'know just to let your adrenalin levels go back to normal before throwing something really nasty at you to kick the glands back into hyper.

 

[A Random Player]

All the exits are automatically blocked or locked.

 

[Incredible Bullshitting Man]

Oh and right after cloud cries over aries's dead body.

That´s a dead giveaway. Whenever you see that scene, you can bet your right lung that there´s Jenova waiting for you just around the corner. Never fails.

Other than that: A vital object the protagonist needs to advance the plot just sits there out in the open, looking all harmless and innocent. You can bet your left lung that a friggin´ huge monster will attack you as soon as you touch the object. So basically like this:

When you come to a large room and see a major character in the game lying slumped against a wall injured, and when you come closer yells something like "No, wait!"

 

[Gamer137]

When you open a door with something call a boss key. That has got to be the most obvious of all.

 

[Get Jiggy]

You've just fought a load of bosses from earlier in the game again, this will be a build up to an even harder new boss. Ninja Gaiden did this when you went to get the Demon Statue.

 

[Nmil-ek]

When the music suddenly changes to something low tempo bu bum bu bum like bloody Jason Vorhees is stalking you >_>

 

[rickthetrick]

Don't forget finally solving an annoying ass puzzle.

 

[GoldenRaz]

When something looks like it will be an absolute walk in the park.
Even worse if a character mentions that in-game.

 

[Halfbreed13]

There is a shiny object in a room.

 

[DarkSplinter82]

When you get seperated/meeting up with some one and its a difficult path having to run around doing all these thing to finaly be like ok im done can finaly meet back up with my partner...Yea right before you re-unite Bam boss.

When your about to save a kidnaped ally.

 

[brainfreeze215]

Well, just like movies, there should be a brief drop in the tension right before a big boss battle. In the movies it's because too much tension is exhausting and if we've just gone through a gauntlet only to be immediately bombarded with tension, we won't be excited and the big battle will lose its importance. It's the same in games, except then we also have to take into account that two big battles back-to-back will drain not only our interest and motivation, but stuff like ammo, which is why SsilverR's first reason is a pretty good one.