[Super long so be sure you have time to read atleast some of it! Nor is this first paragraph a ticket for you to not read the entire idea. I will get very angry if I have to repeat myself.]I\'ve always despised the fact that RPGs have had little to do with character vs enviroment in the gameplay.
I mean, when it\'s foggy yeah, it\'ll block my view; but my iron... my
iron armor
wont rust. I can sit in the fog and kill as many enemies as I want to, and spend days IRL (in real life) sitting there whacking enemies and my equipment just wont be effected by the weather. It makes me (ironically) absolutely
annoyed that my iron armor doesn\'t rust or corrode away.
So, instead of just fighting monsters, players will have to fight their enviroment to some degree. The majority of it is simple, and very little of it\'s really complex. Anyways, on with the filling!
Basic Stuff - Often over-looked by designersInfravision - Always a favourite of players to have in dark dungeons, it allows players to see the infrared spectrum of light; in plain english you see heat emitted from bodies of enemies and friends.
Now, Infravision REALLY helps in the dungeons, because the walls are cold and the majority of the creatures are warm blooded. However, in one too many RPGs i\'ve been able to see invisible and
cold blooded enemies with infravision, when i really shouldn\'t have. Cold blooded enemies dont have any or much body heat of their own; thus they can\'t be seen with infravision very well.
Infravision also doesn\'t improve anything with seeing the landscape. If you\'re on tundra, the land should be pitch black to dark-dark purple. Same with deserts; the landscape isn\'t a boiling white or red. On that topic, infravision continues to funtion flawlessly in enviroments like deserts. A desert is endlessly warm, and any warm-blooded creature would be near invisible, as well as cold blooded creatures because they\'d be warm or very hot! However, cold climates and underwater would increase the power of infravision greatly, as the enemies are on a semi-solid background color... Though fog and being underwater could hamper infravision some (because of the cold air/water/vapour between you and the enemy)
Rusting - RPGs have always been semi-there for rusting and equipment failure, but not fully. If you walked through a water fall your equipment would stay just as sparkling and powerful. However, short-term water contact wouldn\'t really do much... it\'s the long-term on/off water contact that causes rust to form. If a weapon rusts, it loses strength and it\'s edge, though it CAN be a good way to poison something if a peice breaks off inside the body. The only way to stop rust is to stop it before it starts. Coating weapons in metals that resist or dont rust (steel for the former, aluminum and gold for the latter) will preserve the weapon and protect it from rust. Rusted weapons are damaged easilly because the majority of the oxidized iron/other metal is flaked material, as well because of the rusting their damage is reduced to nearly nothing, because it\'d break against even leather armor.
There\'d be different levels of rust:
Very Reflective (The best quality, only possible with waxing)
Reflective (Best possible without adding anything \"Special\")
Shiney (It still reflects light)
Blotched (You can\'t see yourself)
Covered (Severe, but a whipe will clear it and put it to Reflective)
Flaking (Still recoverable, but it\'ll cost you for replacement [metal name here])
Powder (Un-recoverable)
These could also be used to calculate the ability to reflect some attacks on armor and weapons... Very reflective to Shiney would be used, though; Anything below those and the item wouldn\'t reflect didly squat. Losing a weapon to rust is bad, but rusted armor is even worse; it\'s slow and difficult to put on, and once on it isn\'t as mobile or strong. A real problem if you let it develop,
BUT it IS easy to stop and repair. (Just be sure you catch it in time.) Corrosion-like attacks can be put under rusting for effects. Also know that rust often leads to more rust, so it will soon gather strength in destroying your equipment if you dont smack it down.
Complex or difficult to implement - Fighting the terrain and it\'s effects.Snow - Crunch, crunch, through the snow you go. But this is more then emiting a sound when you move. There would certainly have to be different depts of snow, and with depths, there will be penalties to speed, but also bonuses for steath; for the aptly prepared.

A suit or dress of white will make you blend in in a snow storm, as well, some specialized shoes and light armor will increase your speed on this tricky terrain. As well, the cold takes it\'s toll on the unprepared. It will take more time to do difficult or exausting tasks, like jumping and putting on and running in heavy armor. However, that is not to say that heavy armor is not at a disadvantage!
Metal armor WILL slow you down and make you colder, however, if the armor is PADDED and/or if you are wearing some extra clothes you will be able to stay warm; and what does
warm, metal do? It melts snow.

So, if you can have warm or even hot metal armor in a snow storm, you will be able to move at a faster walking speed then you normally could. Some potions will freeze, too.
Deserts - Metal armor isn\'t exactly a good idea here, either, and not wearing any protection will make you boil and become ill due to too much sun exposure. Light, and reflective clothing will help deflect heat and stop you from overheating yourself. Again, if you can color youself or your equipment to the color of the desert you will gain a stealth advantage. You wont suffer much of a speed penalty when walking through the desert, but the stress of intense actions will cause you to lose HP. In this stressed state, casting spells is also difficult. Water and food are also difficult to find for those who dont know where to look for it. The roving sands can also swallow equipment and dungeon entrances... or reveal them.

Potions can evaporate and become concentrated if they\'re not seal properly, as well.
Forests - Lots of cover. However, forests are easy to walk through, and shouldn\'t be that difficult to move through. Very heavy armor might be another story when you reach a slope, however. (tumbling tin men being slaughtered by fast-moving archers comes to mind :rolleyes: ) You can also find lots of food and water, and can actually increase the power of some magical spells. There are lots of creatures, but they arn\'t that diverse.
Jungles - More covers then forests, and thus this causes troubles in movement. There are tons of creatures,
very diverse in their abilities. There are also several natural traps in a jungle like quicksand. However, some things like quicksand can be escaped if you know what to do (quicksand is nothing more then sand particles suspended in water. Yes, you can SWIM in quicksand and you dont get sucked down.) There\'s mud, which if you stand in for too long you\'ll sink down abit and take awhile to get moving in a direction. Vines provide a easy way to get tangled, as well giant spiders webs and hang in the most obscure and lethal of places. Lots of ways to get poisoned, as well... ;(
Swamps - Moving in this place is a nightmare. I pitty tha foo who wears heavy armor. However, you might want to wish you had heavy armor when you encounter some of the swamp\'s monsters. There\'s lots of mud in this place, as well. Sometimes there can be a feild of pure green grass; too bad there\'s water just under the surface. Lots of plant life disguise such things like lakes... and dungeon entrances. A machetty or a heavy sword is needed to cut through all the plants.
Dungeon - Your general baddies, except it\'s totally pitch black the deeper you go. Not much else to say.
Mines - Your general mining enviroment. Lots of things to drop and kill you instantly or atleast maim you long enough for a spider or orc to bite your head off. ;( There\'s often lots of water pools and mud.
Deep interior of the earth; here there be lava - Metal is weakened if it\'s melting point is lower then the highest temperature. Sometimes the metal will actually become maleable enough to re-shape it or melt in your hand/backpack if you go too deep. Potions evaporate if they arn\'t capped. Scrolls and other paper items become severly brittle. Organic armor like leather simply cumbles. Generally not a pleasant place to be. However, there are equipments that are purchasable or enchantments that can be placed on the items to stop them from suffering these ill effects.
The general stuff - That gives it all flavaJust common sense rules over this. Metal can melt or become weaker in hot enviroments. If it\'s cold enough potions will freeze. A wet scrolls\' ink can become blurry. Books can become un-bound if it\'s humid enough and glue was used. Metal melts ice. Fire burns paper. Lava > all.
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Basic stuff like this and counters to their effects can greatly increase the fun (but sometimes frustration) of situations. Traveling in a well ballanced party would become needed for some adventures. The well prepared but weak could overcome the unprepared but mighty. Monsters would be adept at their enviroment, which means a far larger volume of enemies and enemy species.
Generally, Planeshift would become more of a RPG. Players would be asked for their skills more often, and usually be invited into a party when they otherwise might not be. Nothing feels more grand then slashing through a jungle, a
living jungle, where nearly anything can happen to anybody in your party or a monster. More struggle, but more reward for success. And if you fail... Well, you can always respawn.

And finally - more strategy.
If you can change the enviroment to your advantage, you will almost certainly win. Casting a ice bolt onto some water, freezing it, jumping on, having a monster follow you, and then you casting a blaze of fire to melt the ice and drown the beast. If archers are annoying you, just cast some fire on some nearby bush to burn them out. If it\'s too hot, cast a spell that will cool you down. If you dont want to walk through the snow, melt it.

If somethings hitting you from the darkness, throw a lit torch at it!
More player-enviroment interaction is a good thing.