Different areas have markedly different effects on encounters, and the abilities that are needed or helpful to solve them. Major impacts are on the utility of climbing, flight, movement speed, and attack range. But many other impacts are also notable.
- Climax Forest Large trees provide a dense canopy and limited line of sight, but impact movement hardly at all. Flight is heavily restricted in its utility, because if you go high enough to be necessarily safe from melee enemies, those enemies have complete cover in return. Things that can be climbed are pretty much everywhere, meaning that creatures with climbing ability can achieve virtually complete safety from creatures without. This can result in a stalemate, as of course a creature who has climbed forgoes the ability to move much while the ground creatures can easily take full cover just a short distance away.
Jungle Large trees combined with dense undergrowth make movement difficult and reduce visibility ranges to a few meters at most. Ranged attacks are extremely limited in utility, and climbing and flight can get you out of a combat but can't be expected to give you an attack on anything. Combat likely begins at extremely short range, and the fact that everything everywhere is difficult ground makes escaping from melee very difficult to characters who cannot teleport. Closet trolls are far more dangerous than in almost any other terrain.
Swamp Visibility is vegetation limited, but likely extends decently far. Ground varies from hard to walk on to very hard to walk on. Ranged attacks are at a premium despite limited visibility because ground mobility is limited even more. Cover can be taken against flyers, but likely characters cannot get far without breaking cover and exposing themselves to ranged attacks from above. Trees are stunted and characters likely can't climb particularly high and are limited to modest cover from the ground.
Hills Visibility is limited by the hills and valleys. Combat likely begins at a fair distance. There are locations that are better to have (higher ground), meaning that area control matters even though there isn't any cover to have. Flyers can see you wherever you go, and climbing is meaningless (save that it may get you up a hill faster or from an unusual direction). Kiting is very effective.
Flatlands Visibility isn't limited at all, and characters may spot potential opponents days in advance. Kiting is basically unstoppable as there isn't any cover to have at any distance. Being even slightly faster than an enemy is pretty much equivalent to flight as far as avoiding melee is concerned. No ground means much of anything, so area control hardly matters at all.
Tunnels Visibility is super short, and probably requires a light source than can be visually detected from far away relative to the actual limits of LOS. Flight and climbing are pretty much meaningless, because close ceilings mean that you can't use either to get out of melee range. Omnipresent choke points make area control extremely powerful. Ranged attacks are probably close to useless unless combined with allies who can hold choke points.
Large Rooms Visibility is comically short range, and flight doesn't function unless it has hummingbird maneuverability. Climbing may be able to negate melee attacks depending on ceiling height. Cover is likely plentiful. True choke points likely don't exist, but area control is fairly strong because of corners.
Cliffs/Mountains Visibility is broken up by large rocks. Higher ground and large drops are available, so area control is powerful. Climbing can likely get a character to a place where they can take many ranged attacks against an enemy before that enemy can escape or close. Flight is very powerful.
In a fantasy setting there exist places that adventures and encounters can take place in that are not normally accessible without the use of fantastic abilities. These can be accessible in the Heroic Tier with specific abilities, items, or quest rewards. But they cannot be expected locations for adventures before Paragon Tier.
- Undersea Adventure without water breathing is simply impossible. Visibility is limited even without intervening objects. Almost all creatures fly with near perfect maneuverability automatically because of buoyancy. Physical ranged attacks are reduced to melee attacks, but some magical ranged attacks work normally. Normal speeds are reduced.
Cloud Islands Adventure without long distance flight or teleportation is simply impossible. Voids are frequent and require short distance flight or teleports to traverse. Platforms are at different elevations and ranged attacks can be fired from one to the other, but cannot be climbed between at all. Wind and solid fog act as terrain types that specifically monkey with flying characters, leading to an active flying tactical game.
Cocytos Adventure without cold resistance is simply impossible. Brutal winds and heavy weather reduce visibility and limit the usability of flight. Characters with limited cold resistance may need to restrict their movements to covered areas lest they take cold damage in the open. Other than that, you're basically in mountains or hills.
Inferno Adventure without fire resistance is simply impossible. Fires and smoke limit visibility. Characters with limited fire resistance have to stick to the open to avoid damage because the fire damage near cover and features is more severe. Other than that, you're basically fighting in the mountains.
Dreamscape Adventure without oneiromancy is simply impossible. Terrain is malleable, meaning that terrain features, limits, and parameters can change on a round by round basis. The tactical situation, and the value of different kinds of abilities, will change considerably and unpredictably over time.
