As the emotional palette of video games expanded in the mid-Nineties, the horror genre flourished. It brought variation on the familiar themes of performance anxiety, adrenaline rush, and achievement that had been the interactive motor behind Mario, Sonic, Madden, DOOM, and Quake.

Flipping the constant-adrenaline-feed model on its head, games like Alone in the Dark, Resident Evil, System Shock, and Silent Hill put players in claustrophobic environments with controls that often made players feel helpless and vulnerable.

In recent years,  though, the horror genre has encountered some cultural drift. Games like Resident Evil 5 and BioShock 2 still sell millions, but the spark of emotional ingenuity that made SHODAN, Lisa Trevor, and Pyramid Head so terrifyingly memorable seems to have diffused beneath a veneer of action and multiplayer modes.

While some of the old franchises have succumbed to predictability -- the most lethal fault in works of suspense -- a group of newcomers have added much-needed inspiration to the genre. Visceral Games' Dead Space was a lean and steely refinement of the original Resident Evil formula, for example.

Tale of Tale's The Path invited hallucinatory dislocation into its gameplay, while several of Goichi Suda's games have mixed camp and gore in the Dario Argento mold. Last year Climax Studios made Silent Hill: Shattered Memories, an accomplished feat of atmosphere, lurid suggestion, and shrill terror.

Is there hope that this new wave of game designers can rekindle the creative spark of a genre that once seemed revelatory? Is the future of the genre going to be defined by action convention? Or are there dark corners that developers have yet to turn? What design challenges lie ahead, waiting for those developers who try and carry the flame forward?

Mood Lighting and Monster Closets

The predicament in all horror games is the manner in which they deal with combat. In non-horror games it's easy to use combat as the defining gameplay mechanic because there's no need to keep mysterious the beasts lurking in the shadows. In horror, the moment when a monster becomes familiar is when the tension and dread begins to deflate. There's no limit to fear of the unknown, but as soon as an enemy is quantifiable the boundaries are drawn. Fear will eventually become supplanted with frustration or, worse, tedium.

"It's most important to us that the player never gets too familiar with the creatures encountered," said Thomas Grip of Frictional Games, creators of the Penumbra series and the forthcoming Amnesia.

"When a player encounters an enemy enough times, movement patterns and such will quickly get established and the creature will become a familiar gameplay object instead of an unknown, lurking horror."

The traditional way of guarding against familiarity is in designing combat scenarios where the player is notably weaker than she'd expect to be. The Fatal Frame series left players without standard weaponry, providing only a camera to separate them from antagonistic apparitions.

"It's difficult to make players really feel afraid without manipulating the power balance between them and the enemies," Goichi Suda, president of Grasshopper Manufacture and producer on the newest Fatal Frame, told me. "But there are a lot of games that can evoke horror in a player while still using weapon-based combat."

Dead Space

Visceral's Dead Space is one of the most successful combinations of lurking dread and high-intensity combat in recent years. "Pacing is critical in a horror game," said Steve Papoutsis of Visceral. "You need to allow room for the player to feel safe or experience relief in order to deliver the next startle or scare."

"The big challenge is really having all of your primary elements in place early enough so you can play around with them. Horror moments require a full team effort to execute, they rely on Audio, Lighting, Design, Animation, Characters, VFX -- pretty much all of the disciplines on the team -- so having a plan in place and having the elements ready to play with is what really helps."

As much as any other genre, horror games are defined by aesthetic sensibility that must form a cohesive and ambient environment for gameplay. If combat against enemies is going to be used, the enemy encounters must naturally be lessened, placing added importance on using art and sound cues to guide a player's emotions before and after a fight sequence.

"One wants to have a some kind of slower pacing before an encounter, and also provide some kind of build up," Grip said. "It's important to take care of the time before and after an encounter."

"Before an enemy is seen the player's imagination will try to figure out the appearance of a monster and after the encounter the player should hopefully fear the creature. This means that enemies should be placed in such a way that one can get the most out of the time before and after encounters, as it is there that the true horror resides."

Climax's Silent Hill: Shattered Memories made special use of audio design elements to keep players uncertain of what they would discover ahead, even in areas that were clearly demarcated to not have enemies. "We had a dynamic sound system where, if you're not doing something important, you'll have one or two base tracks," Tomm Hulett, producer for Konami on Shattered Memories, told me.

"If something scary happens, we'll amp it up and there'll be a lot more sound going on. Or if we want you to be scared we can amp it up so that you get that subconscious suggestion that something is around the corner."