Chat log with a friend. Here's the verdict:
Sandbox - not affecting your ability to complete the game - whether that means defeating an end boss or experiencing an event of completion (such as a cinematic).
Theme-park - a decision in which only one choice leads to the completion of the game. Such decisions are primarily boolean. (Do X or don't do X.)
Some edits for clarity and understanding.
(9:48:52 PM) Xax: Do you know what 'sandbox' means?
(9:49:40 PM) Azarak: like in computer terms or a box of sand terms?
(9:49:45 PM) Xax: Well
(9:49:49 PM) Xax: I know what a box with sand in it is
(9:49:52 PM) Xax: so video game term
(9:50:11 PM) Azarak: an open ended game, like GTA is considered a sandbox game
(9:50:33 PM) Xax: How do you mean open ended?
(9:51:17 PM) Azarak: like being able to do whatever you want without a linear story
(9:51:27 PM) Xax: Interesting
(9:51:34 PM) Xax: do you remember in D2 there were 6 quests in each act?
(9:51:43 PM) Azarak: yes
(9:52:06 PM) Xax: But you could skip by them and just go for andariel in act one, just kill the bitch and get your free port to act 2
(9:52:31 PM) Xax: never kill bloodraven and get your merc, never have charsi imbue your item, never rescue cain.. would those quests be a sandbox element?
(9:54:07 PM) Azarak: no, because you are meant to do the quests in order to advance. You have to know the andariel thing in advance in order to bypass the other quests
(9:55:46 PM) Xax: Okay, so they're theme park because the main story IS kill bloodraven.. then after killing her you're explained to rescue cain, then after rescuing him charsi explains to go to the monastery... sothe game doesn't explain B until after A, and doesn't tell you about C until after B, and so forth, so that's a main story
(9:57:27 PM) Azarak: yes, using GTA as an example, you can do quest A, B, C, D, or E, and doing one of them will get you to quest F, regardless of which you choose to do. or whose side to take, etc
(9:59:20 PM) Xax: Does there have to be a deciding choice to make it sandbox? For example, in D2 you could rescue cain, or you could not. That's a choice, but deciding NOT to rescue him isn't deciding, because you can do it later.
(9:59:34 PM) Xax: If the game let me get him killed, would that be sandbox?
(9:59:51 PM) Xax: Ie if minotaurs came up and started attacking him, and I let them, and he died,
(10:00:30 PM) Azarak: if making that choice progressed the game in some way, it would be a sandbox game, yes
(10:01:38 PM) Xax: Even if it took me to the same after quest? IE if I rescue him, he can identify my items for free. If I let him die, then the rogue healer learns how to identify items
(10:02:48 PM) Azarak: that could be considered a small sandbox decision
(10:03:29 PM) Xax: What would be a BIG sandbox decision?
(10:04:25 PM) Azarak: if your decision made a difference on what the next quest entailed. Did you ever play oblivion?
(10:04:54 PM) Xax: I'ev been playing gothic 3 lately, I have heard they're a lot alike
(10:05:15 PM) Xax: its first-person, you can takeq uests from the rogues or from the orcs, you can (sneakily) do both but if yo uget caught, bla bla bla...
(10:05:43 PM) Azarak: yes, thats a sandbox game
(10:05:50 PM) Xax: you can either lead a revolution and push the orsc out of towns and reclaim them, or you can become a merc for the orcs and wipe out the rebels
(10:06:15 PM) Xax: But what I was thinking is that the 'end' of the game is the same... the first quest you ever get is 'find Xardas' who is the leader of the orcs, a mage.
(10:06:29 PM) Xax: Well if you go the rebel route, after you liberate all the towns, Xardas appears to put you in your place, and you fight him.
(10:06:30 PM) Xax: OR
(10:06:49 PM) Xax: If you go the orc-merc route, after wiping out the rebels Xardas appears to congratulate you and put you in charge of the town
(10:07:16 PM) Xax: That sounds like your GTA example... you can go the Blood or the Crypt route, but at the end you end up in a gun fight at the bank or whatever, you only affect what team you're fight for in it
(10:08:12 PM) Azarak: if you can make seperate decisions in each quest to affect the rest of the game and still complete it, i think thats a sandbox game
(10:08:23 PM) Xax: I like that definition
(10:10:51 PM) Azarak: WoW I would consider a partial sandbox game. you can pick and choose what quests to do and the end result is that you hit 80 and still have the end game regardless if you saved the beginning town from the wolves or left them to thier fate and went to quest in a diff zone
(10:11:30 PM) Xax: So choosing a class is a sandbox decision, because no matter if you're a priest or a rogue you can still kill the LK.
(10:11:54 PM) Xax: But choosing to level up is a THEME PARK idea, because there is no CHOICE, if you choose not to level up, you CANNOT kill the LK, cannot complete the game.
(10:12:06 PM) Xax: And then deciding HOW you level is is a sandbox decision
(10:12:11 PM) Azarak: Mercenaries was an AMAZING sandbox game. you had your goal (to kill all 52 main bad guys) but you used the 4 different factions to complete the goal
(10:12:26 PM) Xax: was that a ps2 game?
(10:12:46 PM) Azarak: Xbox, i think
(10:16:08 PM) Xax: okay, another one
(10:16:11 PM) Xax: Say... If there are fire elementals that are immune to fire, and ice elementals that are immune to ice, and you get a quest that says 'kill 10 fire elementals' that's pretty theme park, right?
(10:17:11 PM) Azarak: yes
(10:17:36 PM) Xax: fior most classes it wouldn't matter, but for a mage, dk, warlock it would affect your roation and stuff
(10:18:00 PM) Xax: now anothe quest could be... "Kill 10 elementals"
(10:18:08 PM) Xax: Any elementals, even earth elementals that are only immune to nature.
(10:18:25 PM) Xax: This way you could HAVE fire elementals that are immune to fire
(10:18:31 PM) Xax: without everyone going "nerf XYZ!"
(10:19:29 PM) Azarak: yep
(10:21:05 PM) Xax: Okay, another point
(10:23:59 PM) Xax: Okay, this is primarily an MMO problem, it doesn't affect small-world or single player games
(10:26:05 PM) Xax: In a single-player game, the developer decided goal is 'reach end boss/event' - simple enough. If you must complete the quest kill 10 rats to get there, its a theme park quest. If there are only 10 rats in the game and you killed 1 before you got the quest, then you have affected your chance to beat the game, so rats are a themepark concept in that game.
(10:27:02 PM) Xax: But in an MMO, there is no 'end boss.' In fact, there isn't even a quest to kill the LK, is there? If you decide to do that raid, its YOUR decision, not the games.
(10:29:02 PM) Xax: So for MMOs, sandbox can't mean 'affects your ability to complete the game' because there is no 'game' there is only 'goal' - if you are doing Hodir quests, the 'game' is to reach exalted. If you are playing the AH, the 'game' is to profit. You can set a specific goal if you like, 50k, 100k, gold cap.
(10:29:40 PM) Xax: So I think a good definition for sandbox in regards to MMOs would be' affecting your ability to complete the end goal'
(10:29:51 PM) Xax: where 'goal' changes based on activity
(10:34:12 PM) Xax: I think a good example of explaining sandbox dceision in MMO would be an item search. If you are after Bone Arbiter, and you down Marrowgar and it doesn't drop, you can make the decision to kill other bosses, and it will not affect your ability to get bone arbiter. In this case, sandbox would change to mean 'affects your ability to get bone arbiter' - and you can kill every enemy in ICC and it won't affect your ability to come back next week.
(10:36:07 PM) Xax: Alternatively, what WOULD affect your ability to get bone arbiter to drop? Having other users in the raid affects the CHANCE you get it, but does not make it impossible that you'll end up with it. It makes achieving your goal more difficult but not impossible... it's like wearing low level armor to fight the last boss - more difficult, but not impossible. so filling your raid with 2h users is still a sandbox decision, does not affect your ability to achieve your goal.
(10:37:34 PM) Xax: The only theme park decision you could make in that goal is choosing not to log in next week - andt hat is only temporary. Not logging in for the raid reduces your chance of success to 0% for that week - like choosing not to kill andariel, you will never reach baal
(10:52:28 PM) Azarak: those are all very good points
(11:03:11 PM) Xax: Is there a point where sandbox decisions can become theme park decisions?
(11:03:41 PM) Xax: Like in the past you might be able to say 'this decision does not affect my ability to reach my goal' but when you say it now, its 'this decision DOES affect my abiilty to reach my goal'
(11:04:59 PM) Azarak: im not sure. I was thinking about your example of letting a guy die, but if you let him die and then it says: "quest failed" and you cant advance until you save him, then it was never a sandbox decision to begin with
(11:05:51 PM) Xax: True, it was a theme park decision, which means 'not a decision at all' since you have to choose a specific way or you cant win
(11:06:43 PM) Xax: I was thinking on the 'Get Bryntrol' goal, saying 'next week I wont raid' only affects yuor ability to get it NOW, but you can run the week after, and after that, so its a sandbox decision to raid this week or next week, but what about on the last week?
(11:07:15 PM) Xax: On the last week, its 'raid now, or never raid' and when you goal is 'get bryntrol'... raid never means you fail your goal
(11:07:48 PM) Azarak: that would assume there is a last week in a never ending game\
(11:12:13 PM) Xax: My goal is... WORLD FIRST 85.
(11:13:06 PM) Azarak: that rules out sandbox gameplay, then
(11:13:15 PM) Xax: Not so much.
(11:13:33 PM) Azarak: your goal has become theme park in that you need to quest and level
(11:14:35 PM) Xax: True. But it remains sandbox in HOW I quest and level. For example, I assume whoever is competing with me has a pretty fast way to level... But I odn' tneed to be PERFECT, I just need to be... better than second place
(11:15:00 PM) Xax: If the 2nd place guy won't hit 85 until 10 seconds after me
(11:15:16 PM) Xax: Then I have 9 seconds of sandbox time, where I can run around in circles around the final quest turn in and STILL accomplish my goal
(11:15:28 PM) Xax: in this case choosing to run circles in a sandbox decision; does not affect my abiilty to be world first 85
(11:16:25 PM) Xax: however, if I only have 9 seconds left til he dings 85... my SANDBOX decision 'run circles around quest giver or turn in quest' becomse a THEME PARK decision, because if I choose one way (circles) all of a sudden I lose.
(11:17:05 PM) Xax: It USED TO BE a sandbox decision, but because the goal is time-based, after a certain time a sandbox decision becomes themepark
(11:17:58 PM) Azarak: self motivated goals seem very borderline to me
(11:18:34 PM) Azarak: though i guess alot about MMOs is borderline. Its neither sandbox nor theme park
(11:19:23 PM) Xax: Counting achieve system, 85 is developer rewarded, however for MMOs, since there is no singular developer goal 'kill last boss,' only self-motivated goals exist