You say art and unique landmarks... but you have to look deeper than that. By deeper I mean whats really occurring within the player. What you are looking for is "emotional response". Once you find out what triggers an emotional response, then the rest is easy. One way to trigger an emotional response, and it pretty much…
Something with a bit of a challenge/ randomness or something which seems logical to happen (ambushes...etc). Take Skyrim for example, you could be taking a nice stroll along a path then out of nowhere a pack of wolfs try attacking you or just to making more interesting two dragons. Also when going through caves/ mines…
Good exploration needs stories, lots of them. Something needs to happen when you find a new place to explore. The dungeons I most enjoy finding in Skyrim are the ones that have quests that only start when you find the place. For example, some of the dragon priest tombs initiate a quest when you arrive, like Forelhost or…
Personally, I love being able to completely lose yourself in a game world and have the option to do anything. Minecraft is probably the best example.. I love just exploring and finding interesting sites and landmarks. Going down into caves and finding a really cool waterfall dropping right down to the bottom of the world..…
While story helps with exploration, I always loved games where the exploration told some sort of story just through the environment. Like you explore and see a giant crater in the ground. Rather than have some quest tell you what happend there I think it's fun to have a player explore and play detective to look for clues…
So I guess Believability,Immersion and Emotional Response? 1.It doesn't really have to be super realistic and be a one to one representation of what happens in real life.Things should sort of function as they logically would.Have it at least based of reality to make them believable,ground it so to speak.Good examples would…