Mushroom Kingdom
General
Info
Background
Layout
Hazards
Item Appearance Spots
Character Appearance Spots
Strategies
-Luigi
-Mario
-Donkey Kong
-Link
-Samus
-Captain Falcon
-Ness
-Yoshi
-Kirby
-Fox
-Pikachu
-Jigglypuff
My Opinion
General Info
Mushroom Kingdom will seem very familiar to those of you who have played the old school Mario Brothers game (I have). It is modelled after those games. Mushroom Kingdom is a secret stage in Smash and will only become available to you if you beat the single player mode with all eight original characters, so if you haven't done it yet, get cracking.
Background
There are lots to see in the background of Mushroom Kingdom. You can see the funny stair that Mario has to climb at the end of most levels and the little castle. Further in the background, you can see Koopa Troopas and other Mario's enemies doing their things.
Layout

As you can see, Mushroom Kingdom has a very weird layout. Unlike all other stages, there are no pits on the sides of the stage on Mushroom Kingdom. Rather there is only one pit in the middle of the stage. On the left side there is a solid ceiling(1) that has a warp pipe(3) on it that covers the ground(2) below and makes that side sort of like a tunnel. Beside where the solid ceiling ends is a platform(4). On top of the pit in the middle are two platforms(5) connected by a pulley system. On the right side there are two more platforms(4) and then there is one more warp pipe(3). On the left wall of the pit there is a sewage outlet(6). Since there are no pits at the sides of the stage, a player can keep walking and go over the side boundaries.
Hazards
There are plenty of active and passive hazards on this stage, just like there are on any of Mario's levels. I'll talk about the passive ones first. Passive hazard number one is the warp pipes. If you stand on the warp pipes and tap the control stick down, you will be transported to the other warp pipe... most of the time. If the other warp pipe has a man eating flower in it, you will then exit through the sewage outlet and into the pit. So make sure there's no man eating flower on the other pipe and be ready to jump out if you are dumped out at the pit. The other passive hazard are the two platforms over the pit. These two platforms are connected together by a pulley system. If there is more weight on one platform than the other, than the platform with the weight will sink, pulling the other platform up slightly. Eventually, the pulley system will have taken all it can take and the string will break, and both platforms will fall into the abyss, along with whatever is on them at the time. The platforms will regenerate after a few seconds of falling down. The lesson here is don't stand on those platforms for too long or they will drop you into the pit. Now I will talk about the active hazards on this stage.
Active Hazards
Man Eating Flower / Piranha Plant
Damage: 5%
Reach: Medium
Flight Path: Straight Up
Attack Description: One of Mario's classic foes, the man eating flowers
will periodically come out of the warp pipes and bite anyone above in
the arse. If you happen to get hit by the flower, you will receive damage
and will fly upwards a bit. You can take revenge by hitting the flower
with a power move and the flower will probably die. Remember, no matter
how many flowers you kill, there will be more to take their place. If
a flower is on the other warp pipe and you try to use the warp pipe
shortcut, you will be dumped into the centre pit via the sewage outlet.
POW Block
Damage: 20%
Reach: Anyone who happens to be standing on the ground when the POW
has been hit
Flight Path: Straight up
Attack Description: Another object from Mario's younger days, the POW
block is a devastating weapon that can be used against enemies or your
enemies can use it against you. The POW block is a blue block that can
appear either on top of the left warp pipe, above the left platform,
the two pulley platform, or the upper right platform. Only up to one
POW block will be on stage at any given time. If you hit the POW block,
anyone else who happens to be standing on the ground will receive a
lot of damage and fly upwards. The POW hit is very strong and can kill
light characters at about 60%. Be aware that only the person who hit
the POW is immune to it. Even the person's teammates will get damaged
if they happen to be on the ground when the POW is activated, so make
sure your teammates are aware of your intentions or are in the air when
you hit the POW to avoid accidentally KOing your buddies. The POW block
can only be broken by physical hits. This means most projectiles will
not activate the POW. You can, however, throw a person into the POW
and the POW will activate. I don't recommend doing that though because
the POW will damage you in this situation and any KO the POW gets is
awarded to the person who hit it, which in this case the guy you threw.
Be very careful with the POW. It can be your best friend or your worst
enemy on this stage. Oh, almost forgot, CPU players will never hit the
POW on purpose.
Item Appearance Spots
Items will appear on the left of the left warp pipe, between the solid ceiling and the platform on the left side, on the left side platform, pulley platforms, right side platforms and on the left and on top of the right warp pipe.
Character Appearance Spots
The appearance scheme is pretty weird on this stage. 1P starts out on the platform on the left side while 3P is directly under 1P. 4P starts on the higher platform on the right side and 2P starts on the lower platform. The character reappearance spot is above the two pulley platforms.
Strategies
Here are some strategies I can think of for this stage.
-Always try to be the person to hit the POW Block. You don't want anybody
else hitting it since the POW can kill you.
-If you stand really far to the right side of left side, you can easily
kill your opponents since you are very close to side boundaries. Just
be aware that your opponents can easily kill you too at that position.
-Since the stage extends to the side boundaries, red shells become a
legitimate killing weapon. If the opponent is on the top left area left
of the warp pipe, in the left tunnel or right of the right warp pipe
then chuck a red shell and it might just bump your opponent outside
of the boundaries. Just make sure you are not in the shell's way when
it's activated.
-Use the warp pipe to escape to the other side of the stage when the
fight gets out of hand.
-It is possible for some characters hit other people through the solid
ceiling on the left side, so if your character can do so, use the move
to hit people above on the ceiling and those people can't really retailiate
against you... well, it's possible for the player under the bricks to
be hit by an attack above, but the chances of that is very slim.
-If a big item (barrel or crate) appears on one of the pulley platforms,
don't go and pick it up. If you do, the platform will fall and by the
time you actually throw the item, you may be too deep into the pit to
get back out.
Luigi
Luigi is okay on this stage. He isn't especially good or bad on Mushroom Kingdom.
Mario
Mario is about the same with Luigi. Seems that he still remember somethings from back in days when he was 2D.
Donkey Kong
DK is okay on this stage. Just watch out for the pit in the middle since
DK will have a bit of trouble getting out of it.
There's also a trick DK can do on this stage. In the left tunnel,
DK trap people there using the Hand Slap (down B). The solid ceiling
will bounce the victim back down to floor for another hit, so it's almost
impossible for people to escape this combo on their own.
Link
Link will do fine on this stage, as long as he doesn't fall into the pit for no apparent reason.
Samus
Samus loves this stage. She can easily snipe people with her charge shot and the platforms allow Samus to use her air moves and screw attack easily.
Captain Falcon
Captain Falcon is pretty good on this stage. It is flat so Falcon can use his fast running speed and he can also use his air moves here.
Ness
Ness will survive this stage if he doesn't fall into the pit in the middle. The pit is narrow enough to make it tough for Ness to get out by using the PK Cannonball technique. Ness tends to self destruct a lot of this stage, so watch out for that pit.
Yoshi
Yoshi is okay on this stage. Lots of platforms means he can jump around and egg people. Nothing to complain here.
Kirby
Kirby is pretty good on any stage, so you shouldn't be too concerned about using him on Mushroom Kingdom. There isn't many spiking opportunities here but Kirby can use his close combat skill to dominate the field.
Fox
This stage is pretty good for Fox. He can shoot people with his blaster and juggle people here. What more does he want?
Pikachu
This stage is pretty good for Pikachu also. He has a lot of opportunity
to thunder people and can use his formidable air attacks here.
Jigglypuff
Jigglypuff is okay with the stage, but you always have to be careful with the ever so fragile Jiggly who dies so easily.
My Opinion
I don't really like this stage, because it's really easy to get killed here but it's hard to get a lot of KOs. This statement might seem a bit contradictory, but it is true. I never get a lot of kills when I play against cpus on Mushroom Kingdom and I seem to die more here than usual. It's hard to killing people over the left because there's a warp pipe in the way and killing people in the tunnel usually doesn't result in a point since your victims touch the ground before they go over the boundary. It's easy to die here because if you stand really close to sides, your opponents can easily kill you and the pit is hard to get out of. Of course, this is only my personal opinion. You might find the stage fun. None of the Smash stages are really terrible so I don't really mind playing on any stage.