Game Mechanics What makes a good platformer A.I?

PlayerOne

Member
What makes a good platformer A.I? What makes it fun or challenging? I need any and all input on this particular topic as I'm currently at the stage where I have to build my games A.I. All opinions are appreciated.
 

Guitarmike

Member
I look forward to seeing the responses to this post as I am working on a platformer, too, and struggling with the same issue. I think limited unpredictability is important. It shouldn't feel like an algorithm. In the game I'm working on, enemies pause for a random amount of time when facing off with the player before striking. It's "limited" unpredictability because the player knows the enemy is going to strike soon but my goal is to make it so the player has to really pay attention to counter an attack when it comes. Also, enemies should behave like people (or whatever) acting in their own self-interest. They shouldn't dive off of big cliffs while chasing a player or run into situations they can't win.
 
I think it can depend on the game.
The Mario series has a great variety of simple AI. With Goombas and Koopas being pretty passive but with small differences like Red Koopas not walking off edges. Then you have more aggressive enemies like Hammer Bros. who jump around throwing hammers in a way that makes them a little more difficult to approach and defeat.
But if your game is a little more serious or actiony, then enemies that walk back amd forth just aren't going to cut it.
I think what makes good AI good can be a lot of things. They shouldn't be too predicatable, the random pause @Guitarmike mentioned is a wonderful idea.
The AI should also be fair when possible. A good example of this is the knight enemies in Zelda 2. The can attack high or low but telegraph their attacks with just enough time for you to block if you are quick. They also like to keep their distance a little bit instead of just running through you, so they are moving back and forth to keep in arms reach. Makes them feel a little more alive.
 
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Taddio

Guest
I kind of like games where the A.I. gets a little bit "dumber"/weaker when you run low in HP or in desperately bad situations. I like that feeling of "Phewwww, I barely survived that one" when you manage to get out of a hard part with just a little bit of health left.
There's other ways to help get that vibe too, but that's definately one of them.
A bunch of FPS have their bots blindly aiming like the bad guys in Rambo when they're in your back, or when there's just too much of them. Helps me feel invincible!!
 

PlayerOne

Member
I kind of like games where the A.I. gets a little bit "dumber"/weaker when you run low in HP or in desperately bad situations. I like that feeling of "Phewwww, I barely survived that one" when you manage to get out of a hard part with just a little bit of health left.
There's other ways to help get that vibe too, but that's definately one of them.
A bunch of FPS have their bots blindly aiming like the bad guys in Rambo when they're in your back, or when there's just too much of them. Helps me feel invincible!!
You're refering to dynamic difficulty. The better you are the more difficult it gets and if you take damage it goes easier on you. Resident Evil 4 / Biohazard 4 has this; Not that it tells you anyway.

I'm still working out the A.I. So far I'm trying to "spam" weaker enemies to get a sense of insanity the player will face. Still trying to decide enemy types. I'll take enemies "pausing" at random intervals into consideration.
 
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Taddio

Guest
You're refering to dynamic difficulty. The better you are the more difficult it gets and if you take damage it goes easier on you. Resident Evil 4 / Biohazard 4 has this; Not that it tells you anyway.

I'm still working out the A.I. So far I'm trying to "spam" weaker enemies to get a sense of insanity the player will face. Still trying to decide enemy types. I'll take enemies "pausing" at random intervals into consideration.
Yep. It really does enhance user experience, IMO.
This is a cool read to get some hacky ideas as well
https://www.google.com/amp/s/www.po...017/9/2/16247112/video-game-developer-secrets
 

PlayerOne

Member
Yep. It really does enhance user experience, IMO.
This is a cool read to get some hacky ideas as well
https://www.google.com/amp/s/www.po...017/9/2/16247112/video-game-developer-secrets
Thanks. Interesting read so far and bookmarked. May as well add one more to the pile: In Uncharted - Uncharted 2 I think - enemies at the start of ecounters have a 0% chance of hitting the player. That way the player can get a few shots in.

I'll put this here for anyone interested. I also recomend GDC video's as well.

 

Danei

Member
I like a variety of enemies with significantly differentiated movement patterns or behaviors, because their presence then combines in interesting ways. If guy1 chases you, guy2 walks back and forth and shoots when he sees you, guy3 hops around erratically, guy4 swoops in and drops bombs on you, and guy5 (a decapitated medusa, perhaps) flies across the view in a sinewave, combining any 2 or 3 of them is going to result in a relatively unique situation for the player to deal with in terms of movement, timing, and strategy. Or all 5 of them when it's time to ramp up the difficulty and make the player cry.
 

PlayerOne

Member
IMO, if the enemies move towards you or shoot in your direction after being alerted, its good enough AI.
Then I have good Ai since my enemies can run, walk, reload, shoot, throw greandes, and duck and shoot. Thats just the first enemy. Lol.

I like a variety of enemies with significantly differentiated movement patterns or behaviors, because their presence then combines in interesting ways. If guy1 chases you, guy2 walks back and forth and shoots when he sees you, guy3 hops around erratically, guy4 swoops in and drops bombs on you, and guy5 (a decapitated medusa, perhaps) flies across the view in a sinewave, combining any 2 or 3 of them is going to result in a relatively unique situation for the player to deal with in terms of movement, timing, and strategy. Or all 5 of them when it's time to ramp up the difficulty and make the player cry.
Interesting. Thats usally reserved for more insane games. Reminds me of that NES game with that floating head in the backdrop of a city. It was side scroller and it was made to be terrible. Can't remember the name.
 

Danei

Member
Yeah, I mean it doesn't have to be fiendishly difficult.
That's just my personal philosophy as a designer: Crush and tear. Rend and maim. Lay waste to the player. Gorge upon the viscera of the fallen as my laughter echoes through a blood-drenched universe.

But even without that, the principle of differentiated enemies to create dynamic and memorable gameplay situations still seems solid. I saw a GDC talk that touched on this, and I think the speaker called it "orthogonal unit differentiation".
 

PlayerOne

Member
Yeah, I mean it doesn't have to be fiendishly difficult.
That's just my personal philosophy as a designer: Crush and tear. Rend and maim. Lay waste to the player. Gorge upon the viscera of the fallen as my laughter echoes through a blood-drenched universe.

But even without that, the principle of differentiated enemies to create dynamic and memorable gameplay situations still seems solid. I saw a GDC talk that touched on this, and I think the speaker called it "orthogonal unit differentiation".
Was it this GDC talk?

 

Rayek

Member
Enemy AI, or perceived AI and behaviour is also entirely situational, I found. I recall this old game called "FRAK!" on the 8bit BBC, and the 'enemies' just stand in the way, unmoving, being obstinate. The placement of these beasties is very well thought out, and even though this is a very simple puzzle platformer game, the enemies have a certain personality (mostly due to the cartoon graphics) and perceived 'smartness' because they are exactly in those places where you have to deal with them before you can finish a level.

Although they are static, they still feel like they have a mind of their own. Of sorts.

It goes to show that AI is as much in the eye of the player as it is the game designer's job.
 

Niels

Member
It really depends on the game, but generally I noticed that simple patrolling AI is good enough for platformers/metroidvania's.
 
L

Ludo Design

Guest
Good AI works toward assisting in the game's immersion or joy factor, typically by following these design constraints:
  • Follows a strict set of common sense rules.
  • Is usually weak and simple (it's only complex if it absolutely must be complex, try to avoid needing complex AI).
  • Comes in a high gameplay variety and combination variety, i.e. several very unique enemies with different tactics.
  • Does not have to be dynamic (as this increases complexity), but that does add gameplay variety.
  • Is appropriately fitted to the gradually increasing challenge level of the game (not frustrating, not a pushover, just right).
    • The Konami/Castlevania metric ("a boss passes the test if you can beat it without getting hit once") assists in accomplishing this.
    • Playtesting with volunteers of various gaming literacy levels can assist with this.
  • Does not encourage unintended gameplay that is not fun for the player.
And more constraints can be found but these are generally the big ones.
 
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