How best to handle stealth missions

[whitesphere]

I'm working on a stealth mission for my game, so the player can act as a spy, sneaking past guards and taking the secret documents, using them to overthrow a regime.

It's fairly obvious that, if a guard sees or hears you, you're in trouble.  Now, I've calculated a percent chance of detection, but am wondering how best to handle the shades of grey between 0% (not seen/heard) and 100% (definitely seen/heard):

1. Use the RNG to determine if the user is seen/heard. 

2. Use a cutoff threshold, below which the user is never seen/heard, above which the user is always seen/heard

3. A combination of the two above

I recalculate the detection chance whenever the player or a guard moves.

But, I can see real pros and cons to each side.  The RNG can keep the stealth mission challenging, because the same run can have 2 different outcomes.  I could argue this is more "realistic" because I'm obviously not simulating every detail of detection (just line of sight/hearing, equipment noise, obscuring tiles and so on).

The cutoff threshold is more predictable, so the same run always gets the same result.  This might be less frustrating for the player.

So, which would you prefer in a stealth mission?  Where do you draw the line between challenging and frustrating in such a mission?

The way I'm doing this, the stealth missions themselves are an optional mode of play --- you can do the more typical RPG combat if you wish.

 

[Stridah]

this is an interesting topic and i am hoping someone with alot of stealth experience can post a bit of a tutorial.

here is my opinion on it though, if you are hiding in the same spot, on two different play throughs you should not have drastically different results. I think challenge should not come from a dice roll, it should be installed through the gameplay whether it be through guard positioning or game mechanics such as utilizing resources (toss bait, make noise, etc).

as a general rule i think people hate random, whether it be invisible random encounters or what not.  

 

[Alexander Amnell]

The way I'm doing this, the stealth missions themselves are an optional mode of play --- you can do the more typical RPG combat if you wish.

Make them as difficult and 'realistic' as you want them to be then. An ultra hard stealth mission that interrupts gameplay in a non stealth-based game and leaves the player trapped is infuriating; on the other hand an optional challenge for the players that are into that sort of thing are always great. (just, please don't go the route of having the player smash lights to gain more darkness to hide in, it just makes no sense under any circumstances that that would let you catch anyone unawares though it is utilized so bloody often that it's close to a standard.)

Also, I really like the random idea for variable detection, but there is a baseline (i.e. positions you can get to for guards with a 0% chance of detection)? Making risky moves possible to pull off but variable is one thing, but there should still be a way for the ultra careful to find that guarantees them not be detected under the exact same circumstances each time, otherwise the entire mini game becomes random and that's never fun. Thus I vote for 3.

 

[The Prince of Sarcasm]

Or you could, since this is already optional, make the player be able to choose which out of the three he wants to play.

 

[whitesphere]

In the game, it's more you choose how you want to play, than a minigame per se.  

There is, early in the game, a king who asks you the usual "Go talk to the Orcs who are raiding our kingdom" .  But, if you can sneak past the guards upstairs, you can find some interesting documents.  If you then pass these to some revolutionaries, they can overthrow the king.

Or, you can outright kill the king (if you can overcome his guards) directly.  

Or, you can choose to follow the more traditional RPG method and go talk to the Orcs.  

If I implement it right, it'll be a multiple-paths through the game type of deal.  So players who love stealth missions can play most of the game that way.  Or, perhaps try a single stealth mission to solve a quest.  And anyone who hates them can choose a different way to solve the problem.

In the stealth mission, I'm considering that various tiles have different levels of light, and sound, as well as levels of muffling. The player can choose to do things like wear different armor and such to minimize the risk of detection.  And, of course, using a type of non-lethal skill to quickly and quietly knock out guards... if combat goes on for too long, it tends to draw attention for some odd reason.

 

[Stridah]

Whitesphere,

What if you have maybe three different types of guards and they all have different abilities

guard a- struggles to see into dark light, pass him in shadows

guard b-has eagle eyes but bad ears, so you gotta make it behind him

guard c- has eagle eyes and fox ears but add, so you need to distract him

 

[The Prince of Sarcasm]

I like that idea, Stridah. I kind of mixes every idea together.

 

[whitesphere]

Stridah

That is a good idea. I will make sure to do something like that. I already have hearing and sight handled differently.

 

[hian]

As a Stealth genre fan, who's played pretty much everything from early Tom Clancy games, to Tenchu and MGS, I have to say I prefer the MGS system by far.

Stealth gameplay should have clear parameters, because if it doesn't, it becomes frustrating.

MGS handles stealth very simply by having a definite variable for whether you're spotted or not, and then having a much broader variable for enemy awareness.

I.E enemies either see you or they don't, and how far and what they can see is fairly static and easily understood to the player, but then the guards can react to what they see or hear in a distance, which they will then move to investigate.

That's brilliant because it allows the player to have an accurate awareness of enemy detection capabilities, while allowing for some level of organic changes in guard behavior that doesn't immediately punish, and thus frustrate, the player.

I would recommend a similar system, if you're able to. Either the player is visible or not, but depending on a secondary variable related to vision or sound, guards will move closer to the player's position, which will, if the player doesn't move, result in the player eventually being spotted.

This is much better than vague or unspecified enemy awareness variables that makes it very hard for the player to calculate risk and participate enemy capabilities, since that will inevitably lead to players making mistakes based on factors they will feel they have little to no control over, which invariably leads to feelings of frustration.

There is nothing worse in a stealth game than being spotted and not knowing how or why it happened, and having little to no way of accurately predicting how to avoid the same happening again.

 

[Stridah]

thanks guys i feel like placement of npc's if you do my version could make for some really cool combos of stealth moves, maybe ill do it for my stealth mission LOL!

 

[whitesphere]

So, if I summarize the suggestions:

1. Stealth should be predictable in its outcome to avoid player frustration

2. Stealth should calculate vision and hearing acuity separately

3. Stealth should have 2 primary responses:

 a. Guard moves to investigate if above some threshold

 b. Guard spots player if above some higher threshold

Always glad to hear suggestions from stealth mission fans, since I've hardly ever played any (the original Metal Gear for the NES is my most common experience), but think they are essential if I want my game to allow the player to be a spy.  And I think they could be a fun way to play, as long as they're not the only way to play.

 

[hian]

So, if I summarize the suggestions:

1. Stealth should be predictable in its outcome to avoid player frustration

2. Stealth should calculate vision and hearing acuity separately

3. Stealth should have 2 primary responses:

 a. Guard moves to investigate if above some threshold

 b. Guard spots player if above some higher threshold

Always glad to hear suggestions from stealth mission fans, since I've hardly ever played any (the original Metal Gear for the NES is my most common experience), but think they are essential if I want my game to allow the player to be a spy.  And I think they could be a fun way to play, as long as they're not the only way to play.

Yes, I think the above sounds just right. Those parameters are probably the safest ones to go with if you want stealth sequences feel smooth and real at the same time.

Best of luck!