I've been trying to brainstorm some ideas for a project of mine, but haven't gotten too far. As the title suggests, what aspect of an open world game draws you back and makes you want to play more of it? Is it some sort of main story, or is it something else?

Skinner Box. Look it up, particularily the Extra Credit videos on that topic. The highly addicting secret of many open-world MMOS and grindy games like WoW, Diablo, Torchlight, Korean MMOs etc.

Which, ironically, is the reason I never got into them; too much circular "grind so you can get better loot so you can grind to get better loot so you can grind to.... yea." So for me, a strong story is one thing that keeps me going, and a world that feels "alive" and "emergent" (as opposed to "scripted") is what makes me believe an open world is actually open.

Also, atmosphere. Getting lost in the beautiful Skyrim autumn woods on my horse, following a gentle creek as my only reliable indicator (I made it a point not to use the minimap), hoping I run into a village soon because Im running low on resources... mmmm.

Side quests to the main story if they are well done are generally what keep me playing the game and wanting more. However for some games its simple things like crafting where if I want a cool weapon (Not just the strongest but something that stands out, like the Wabbajak from Skyrim) I can go out of my way to get it on it's own little "epic" quest; not just buy 4 resources and smelt.

I have pretty much lost interest in open world games. I don't have a lot of time anymore for games. For me to finish them, they have to have a plot and do a good job of taking you down it. The days of spending 80+ hours on a single game (I'm looking at you FFVII) are long gone, and a game with a solid story and 8 to 16 hours of gameplay have the highest chance of me finishing them. I've owned Max Payne 3 for over a week now, and I'm maybe 4 hours into it even though I think it's a great game so far.

Skinner Box. Look it up, particularily the Extra Credit videos on that topic. The highly addicting secret of many open-world MMOS and grindy games like WoW, Diablo, Torchlight, Korean MMOs etc.

Which, ironically, is the reason I never got into them; too much circular "grind so you can get better loot so you can grind to get better loot so you can grind to.... yea." So for me, a strong story is one thing that keeps me going, and a world that feels "alive" and "emergent" (as opposed to "scripted") is what makes me believe an open world is actually open.

Those kinds of games make me sad and angry. I've been on the receiving end of those tricks long enough to know when someone is wasting my time for their gain. For me open world games are about the experience, not the XPrience. There are games/mods where the stories that come out of them are interesting even to non-players. I have read the Day Z forums and marvelled at the things people have done and been through. But reading about a WoW player spending 2 hours grinding up to the next level? Not so much. Even Minecraft... although I think people are crazy for making those huge machines, I will still check out a youtube video of a 10 story tall minecraft calculator and marvel at the time and ingenuity involved.

I like when I have specific goals that take a few days to earn - mounts, appearance customizations, unlocking a minigame or crafting ability, rewards related to my house/pets/crops if the game has any of those. I also like earning faction reputation or relationship points with an individual NPC if the game actually responds to me differently when I have a higher or lower reputation, and for factions I want to be rewarded with faction tabards or something that shows my rank in my appearance (the winged name system in Dofus is cool).

So do people prefer character development or exploration? Or some combination of both?

So do people prefer character development or exploration? Or some combination of both?

Well, have you seen that system that categorizes gamers by the suits in a deck of cards? Customizers and explorers are two different audience segments. Treasure-hunters are another audience segment - they like collecting stuff and having the ability to show off their collections and wealth to other players. Some games focus on one audience segment, others try to please everyone by cross-rewarding: for example some people like exploring for its own sake, but if you also give rewards for exploring, like story advancement, treasures which are customization options, treasures which are collectibles, and praise for first seeing each new part of the map that builds toward an achievement for seeing every place on the map, then you can make everyone feel rewarded for exploring. The same goes for other activities - you could have a pvp arena that rewarded crafting-related items and appearance customizations and keys to unlock new areas to explore. You could have crafting be important to creating collectibles and collectible displays, appearance customizations, and maybe mounts or pets that aid with exploring, plus gear that helps with hauling back treasure. Or some kinds of crafting, where the player breeds animals or plants, or experiments with chemistry or cooking, could be considered their own kind of explorations, and rewarded with achievements for the player breeding or cooking their first thing in each category, and a complete set in each category.

To wander into the unknown, to explore new places. When I played wow back then long time ago I would enjoy the new environments I discovered(in fact that is what made med play the game as I wanted to see the huge world). In Skyrim it is the great beauty of nature and the world, in Oblivion it was also the nature and new people I would meet with their quests and stories. One word "exploring" covers it all.

It is like traveling without being in need of packing my suitcase or buying a ticket. You travel until you are fed up and leave by closing down the game. Open world RPG games are all that and that makes many people enjoy them.