Video games designed almost entirely by a computer program herald a new wave of AI creativity
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Have a go at the game designed especially for New Scientist by the AI Angelina: "Space Station Invaders"
IT IS never going to compete with the latest iteration of Call of Duty, but then Space Station Invaders is not your typical blockbuster video game. While modern shooters involve hundreds of programmers and cost millions of dollars, this new game is the handiwork of an AI called Angelina.
Software that generates video-game artwork, music or even whole levels is not new, but Angelina takes it a step further by creating a simple video game almost entirely from scratch. "It has only been very recently that we've asked ourselves, could you procedurally generate the whole thing?" says Michael Cook, a computer scientist at Imperial College London and creator of the game-designing AI system.
Angelina creates games using a technique known as cooperative co-evolution. The system separately designs different aspects, or species, of the game. In Space Station Invaders - in which players control a scientist who must fend off rogue robots and invading aliens to escape a space station - the species include the layout of each different level, enemy behaviour and the power-ups that give a player extra abilities. Angelina creates a level by randomly selecting from a list, then scattering enemies and power-ups throughout the level. Enemy movements and combat behaviours are also randomly selected from a list, while the effects of the power-ups are also random.
It then combines the species and simulates a human playing the game to see which designs lead to the most fun or interesting results. For example, levels that are initially hard to complete but get easier through clever use of power-ups are considered fun, while those that are impossible to complete are discarded. Angelina then cross-breeds and mutates the most successful members of each species to evolve a new generation, typically 400 times.
Combining these simple elements can produce surprisingly nuanced effects. For example, in one level of Space Station Invaders the player acquires a power-up that boosts their jump power but quickly discovers the added height still isn't enough to reach the platforms directly above them. To proceed, they must travel to another part of the level. "That was a very precise design of those power-ups to make sure the player couldn't get up too easily to the exit," says Cook.
Angelina can't yet build an entire game by itself as Cook must add in the graphics and sound effects, but even so the games can easily match the quality of some Facebook or smartphone games, with little human input. "In theory there is nothing to stop an artist sitting down with Angelina, creating a game every 12 hours and feeding that into the Apple App Store," says Cook.
So should game designers be worried? "I like to think that Angelina won't steal anyone's job, I think it will actually be a really positive force for designers," says Cook, suggesting that developers could use a system like Angelina as a collaborative tool for designing games. For example, a developer who creates a new power-up for a game could ask Angelina to design a level that would teach the player how to use their new ability.
"I like the idea of a conversation," agrees Mark Nelson of the IT University of Copenhagen in Denmark, but he says a system like Angelina needs to be transparent so users can modify what it considers to be a good game, rather than just producing games at the push of a button. "Designers would find that annoying."
I'm a scientist, get me out of here!
If you want to know what it is like to play a game designed by an artificial intelligence you can try your hand at Space Station Invaders, which was created especially for New Scientist. One limitation is that the player can't die because the AI, called Angelina, can't measure the difficulty of the levels it creates and so can't work out what constitutes an inescapable situation. "If we had introduced death, it would be quite easy for Angelina to produce impossible-to-complete games," explains designer Michael Cook of Imperial College London.
Angelina can only create one level at a time, but Cook says that if it could measure difficulty games could have progressively harder levels.
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