Obstacles
I bet you're wondering what an "obstacle" is. Well, for all intents and purposes, an obstacle is anything in Sweet Home that can be interacted with that hurts you, blocks your path, or impedes your progress in any way. For things that for whatever reason affect your party positively (excluding weapons, items, and...uh...people...), check the Objects Section.
Obstacles that get in your way
Barrier -Only one in the game, and it blocks Mamiya's room. Yamamura will take care of it for you.
Blue Flame -There's just one blue flame in the game, in the Basement blocking the incinerator room. Use the Gem to get past it.
Blue Statue -These get in your way at the most inconvenient times. Many of them can be pushed, but only after reaching a certain point in the game. Others are removed by events in the game, or by Yamamura...
Chasm -A small hole. You can use Wood on a chasm to cross it (beware if the wood breaks, if it does use TEAM to help the stuck character. The stuck character will lose 3 HP every couple of seconds until he/she is either saved or dead).
Fireplace -The Fireplace in the Dining Room blocks the entrance to the Dungeon. After meeting Mamiya for the first time, the fire will go out, and you can enter the Dungeon.
Gap -Only found in the End area. Step up to a gap and you'll fight a clone of one of your characters. After defeating the clone, you can cross safely.
Gate -There are only two in the game, both in the Dungeon. Use the Iron Key to unlock them.
Glass -You can't get past an space with Glass on it. Use Asuka's Vacuum or a Broom to get rid of it.
Green Statue -There is only one of these in the game, fill the Bucket with blood from the fountain, and use it on the statue to remove it.
Locked Door -These won't open unless you use the correct key in them.
Mirror -Stepping in front of these causes you to fight a Mirror. After defeating the Mirror, you can smash it with a Mallet. One of them reveals a hidden passage.
Rock -To get rid of a rock, simply use a mallet on them.
Rope -Ropes block certain areas. You'll have to use Kazuo's Lighter or Matches to get rid of a rope.
Rubble -In one room (and only one room) in the 1st Floor, you can use a mallet to break away the rubble.
Shadows -You can't walk past the shadows. Use the F Light to get rid of them.
Strait -The shrub on one side of a strait is a tell-tale sign that you can use a log at this area of the lake to get across.
Water Statue -These just stand in your way in the Courtyard. Use your mallet to demolish them.
Wood Piles -To get past the wood piles on the Lake, you have to use the Ax (the item, not a weapon).
Terrain that hurts you, or otherwise affects you negatively
Bodies -These are found in the Inner Sanctuary. Standing in the Bodies causes you 10 HP damage to each character standing in it every couple of seconds.
Boulder -These will roll at you in certain areas. They cause 30 HP damage to each character they hit.
Fire (1) -Standing in the fire will cause you 10 HP damage every couple of seconds. These can be put out using the Fire X (except the big fire in the Basement).
Fire (2) -This bursts out of the wall in certain areas. Standing in it causes 10 HP damage every couple of seconds, and it can't be put out.
Ice (1) -Stepping on ice causes your party to split up, and slide downward, usually into Bodies (see above). To prevent sliding, use the Pick.
Ice (2) -This appears in a certain room in the East Wing. Standing in it causes 10 HP damage every couple of seconds.
Lava -Lava flows in the Dungeon. Stepping in it causes your party to split up, and flow into Spikes, much like Ice (1), but the Pick won't help you.
Sand -Exactly like Lava.
Sand Trap -Stepping in a room with a sand trap will activate it (in one room, you have to get the clue from the fresco first). When the trap is activated, the character(s) in it will begin spiraling toward the center, and when they reach the center, they die. To prevent death, have a character stand on the plank in the room, and use the rope.
Spikes -Standing in the Spikes causes you 10 HP damage every couple of seconds.
Sticky Floor -Taking four consecutive steps on a sticky floor causes your character to be stuck. The only way to save a stuck character is to have another character walk up to them and use TEAM to rescue them. If all your living characters are stuck, the game is over. If you wear the Boots, you won't get stuck.
Thorns -Standing in the thorns causes 10 HP damage every couple of seconds. Wearing Gloves prevents damage.
Water (1) -This water is found only in the Courtyard. Stepping in the water causes you to be swept backward and breaks up your current party, and when you reach the wall, it causes 10 HP damage every couple of seconds. To stop the water from pushing you backward, push the statue found in the southern part of the room. The Pick also prvents you from being swept away.
Water (2) -This bursts out of the walls in certain areas. Standing in it causes 10 HP damage every couple of seconds.
Obstacles that fall on you
When you step on certain places, the screen cuts to a falling object, and you're given four choices: Left, Right, Duck, and Pray. Or you can just do nothing. No matter what you choose, sometimes you'll be hit, sometimes you won't (But if you do nothing, chances are, you'll get hit). The only sure way to be safe is to Pray, but that uses up precious Pray Points...The choice is yours. Also remember, falling objects only hurt the lead character.
Chair -Hits for 3 HP Damage. There's 1 in the Dining Room (between the 1st and 2nd Floor), and 2 in the East Wing.
Chandeleir -Hits for 3 HP Damage. There's 1 on the 1st Floor, 1 in the East Wing, two in the Northern Region, and 1 in the Inner Sanctuary.
Statue -Hits for 5 HP Damage. There's 3 in the East Wing, and 3 in the Inner Sanctuary.
Sword (I think) -Hits for 10 HP Damage. There's 1 in the Garden, 1 in the Northern Region, 1 in the Courtyard, 1 in the Basement, and 3 in the Inner Sanctuary.
Enemy Obstacles
Armor -Touching these will either cause you to get in a fight with an Armor (if you're on the 2nd Floor or the Northern Region), or a Knight (if you're in the Inner Sanctuary).
Bat -Touching this causes you to get in a fight with Bats.
Battling Enemy -These are what the enemies you're fighting look like when you attempt to CALL some help.
Gap -Only found in the End area. Step up to a gap and you'll fight a clone of one of your characters. After defeating the clone, you can cross safely.
Mirror -Stepping in front of these causes you to fight a Mirror. After defeating the Mirror, you can smash it with a Mallet. One of them reveals a hidden passage.
Shadows
Touching these shadows will cause you to be transported to a different room in the Mansion. To find out which room each Shadow takes you to, head to the Shadows Section.
Shadow (1) -These go at you in a straight line.
Shadow (2) -Just like Shadow (1), but three times as wide.
Shadow (3) -These will persistantly follow your characters.