Difficulty Tuning Roundup

There are many elements of gameplay that are worth tweaking for harder difficulty modes, provided there is time to test each of these thoroughly against the other modes, and with players of varying skills. I'll investigate a few here.

Time limit. This is a classic difficulty tuner for racing games, and a few platform games-essentially inspiring the player to get to the end of a level or challenge by X time. This usually forces the player into optimal route-finding play and looking at their navigational tools differently.

Had Prince of Persia: Sands of Time embraced non-linearity, we may have had a time limit goal challenge to recontextualize the levels in some very interesting ways. Generally, most racers have a medal-based reward structure where the gold medal will be a very tight time to achieve. Games that have other play types involved in the racing -- F-Zero has combat for example -- end up forcing the player to also optimize those play types, alongside finding the ideal path.

Damage Dynamics. This is the easiest thing to tweak when making a game harder-just make everything hurt more. The problem is that without careful tuning of other factors, such as enemy placement and resources, this can bring about one-hit kill syndrome, which in a 5-10 minute stretch of play can come across lazy and unfair. It's also the easiest way to change the feel of the game from an evaluate/solve game to a predominantly memory-play based affair.

The best difficult modes in games tend to share the same formula for upping the difficulty, which is contextual to the level portion. Sometimes this involves more enemy spawns, and most of the time there's additional damage-and in some places, less ammo.

Simon says. If the game is dependent on button presses, like DDR, Beatmania, or Guitar Hero, then demanding more presses per time unit makes sense as a difficulty increase. Pressure is increased through the players having to parse what they see, and combine that with what their currently engaged feet, fingers, or other digits are already doing.

Increased AI aggression. Halo 1 and 3 are perfect examples of how to pull this off, as are the Infinity Ward installments of the Call of Duty series. Sometimes, the enemy just behaves more aggressively, forcing the player to act more quickly and confidently, rather than wait around trying to aim a perfect head shot. In Halo, the grunts will do suicide kills in the harder difficulties.

The enemy AI in Halo shows increased aggression at higher difficulty settings.

Make your enemy AI take more risks, but on the flipside don't make the enemy AI be able to see the player from a million miles away with the aim of a laser-eye-surgeried hawk, or you'll get a Mega Man-style scenario in which players feel cheated through an unknown and unseen kill, such as from an off-screen bullet. In some contexts it's realistic, but in most games of this sort that I've played, it's rarely fun. It could just be me, but it made me stop playing Medal of Honor: Airborne.

Reduced neutral zones. This is when safe areas and unused areas are removed or replaced with hazards, such as spikes you can't stand on or instant-kill zones. The Challenge levels in Valve's Portal are a great example. This has the added side-affect of pin-holing the player's focus on very few options, and with good level design can create a high-pressure puzzling environment.

HUD restrictions. In some games, challenge can be tuned by altering the interface. Games with multiple feedback systems work best, as numbing or reducing just one of your in-game senses can cause player decision-making to be more tense. The Metal Gear Solid series has done this since the beginning, where harder difficulties would remove the in-game radar, meaning the player had to rely not only on their memory of the game's layout but also their reflexes and knowledge of the AI behaviors to survive.

Resource stinginess. The Resident Evil series chose to limit ammo as difficulty levels ramped up. This results in extreme tension, helping to add to the horror, but also greater pressure on the player to be resourceful. Many skillful Professional Mode Resident Evil 4 players rely on sharp-shooting kneecaps to bring the enemy to its knees, then finish it off with the knife to get through the game on a minimal bullet-budget.

The Illusion of Fairness

It's a common perception that the key to keeping a challenge fun for many is to make it feel fair to the player. Of course, classic video game scenarios-such as one man against an army of aliens, or a flying saucer against numerous battalions of space ships-is completely unfair.

Few games, if any, are "fair." The illusion of fairness to the player is what's important, and this comes in the form of convenience mechanics. This includes things like health packs placed before and after sections with large enemy counts, generously placed ammo pick-ups, strength/weakness matrices for certain weapons a player may have versus present enemies onscreen, and smart checkpointing that checks in regularly, usually before and after these kinds of areas. Above all this, communication and feedback to the player is necessary. Here are some examples.

Physical feedback. This is the staple of many FPSes, but Resistance: Fall of Man lacked it (the game has since been patched for Sony's new rumble controller), and in my opinion really suffered for it. Aside from obvious elements like weapons firing and vehicles moving, most games nowadays tend to use feedback in the controller to communicate how close you are to death.

For example, if the controller is at a light stage of rumble, the player is being attacked, but is not about to die, or the enemy is attacking from afar with weak munitions. If the rumble is intense, chances are that the enemy is attacking at close range, or with an attack that is bringing the player nearer to death.

Hazard feedback. Flashing red markers onscreen and other screen filter effects are great for games where your avatar is in 3D space and can be attacked from all angles. Half-Life pioneered this with 4-way red flashes to indicate if damage was greeting you from the sides, behind or in front, but later games like Call of Duty enhanced it by specifying exactly which angle.

Loss feedback. This is somewhat rare in games. Usually, this feature is considered taken care of if the game is tightly designed. Some games, such as the critically acclaimed racing game Burnout, use an instant replay function. Team Fortress 2 also does a great job of telling players how they died. Upon being killed, a player's assailant is displayed onscreen immediately crushing any illusions that the player was robbed of a victory by a poorly built game-an illusion suffered by many sore losers (myself included).