GURPS Speedsters

What is a Speedster?

I would say the defining trait of a speedster is mobility. Most run fast, but any movement mode is viable and speedsters often have more than one - even if the others are gimmicks or variations of thier core ability.

High mobility alone wont do damage and its of limited defensive value, mostly staying out of reach or making opponents have to deal with heavy range penalties.

Speedsters often have high reflexes (DX), Enhanced Defense (especially Dodge), and Altered Time Rate for further defenses. Damage Resistance (Crushing) is also common to help them cope with falls or being tripped. Danger Sense or 360 degree senses, even Cosmic Defense on Dodge are also helpful here or Obscure (anti-targeting) usually as a speed blur. The primary speedster defense is avoiding getting hit.. 

Offensively speedsters may rely on attacks based on momentum or a special effect of their powers. Vibration, Teleport, Throwing things, Martial arts, time powers, and more can all apply to speedsters.

Special Effects

As with most Supers builds the special effect is key to getting a good set of useful abilities.

Energy Form

Energy forms like light or electricity are often seen as fast and can give good versatility and speed. Insubstantiality, Flight, and ranged energy attacks are typical. This type usually has above average DX and agility and excellent mobility. Its a good choice for a newer player.

Examples: Lightray

Enhanced Speed

Easily the most common type is the speedster who is simply just fast. High DX, Basic Speed, and Move are standard and Enhanced Move is very common. Enhanced Move with Second Nature (GURPS Power-Ups 4: Enhancements) changes Enhanced Move to Basic Move, allowing for good combat mobility at a decent price and 1/10 the total Basic Move counts as a Step so they can avoid penalties for a Move and Attack maneuver. Certain cinematic options such as Heroic Charge, slams, or techniques are also a good option. Altered Time Rate and Enhanced Time Sense are also common here, at least for Four Color supers.

Examples: Flash, Makari, Quicksilver, Superman

Spatial Manipulation

An unusual type of speedster is one that does not have superhuman reflexes but can either bypass or alter the distance between two or more points. Most often this is based on teleportation but it can also use stretching or size alteration powers to either bring objects closer or extend your own reach and step.

Warp is the most common power, but Stretching, (Growth/Shrinking) are also seen in the comics.

This type of speedster is generally more of a challenge to build and play. They tend to be less effective in combat than the Enhanced Speed type but often more versatile and effective outside of combat.

Examples: Ant Man and Wasp, Dr. Manhattan, Mr. Fantastic, Nightcrawler, Spot

Time Manipulation

More common than spatial manipulators but far less so than enhanced speed types are those who can accelerate or slow down time.

Altered Time Rate is the goto ability here but Afflictions to slow others down, Time Stop fields (Jumper) and other abilities are typical. They may attack by aging things to dust.

Examples: Chronos and several time traveling gadgeteers.

Character Design

Speedsters tend to rely on avoiding being hit but no matter how good your dodge is a critical hit can ruin your day. Area attacks are also a vulnerability. Speedsters tend to be glass cannons, they can hit fast and often hard but cannot take a hit themselves.

Speedster bricks are an exception in that they have bodies tough enough to withstand the stress of high speed and martial artists may have learned how to toughen themselves up.

As a general rule though the speedster needs to be able to zip around the battlefield and get out of others reach while still being able to attack.

High HT, Hard to Kill, Regeneration, and even Extra Life are all useful for when things go wrong and you take that big hit meant to stop the brick!

Armor Piercing is especially useful on offense, hit often for lower base damage but good penetration - ether from accuracy or penetrating power. 

Attacks with Aura (counterpunching) or Area Effect/Emanation (rapid attacks) are effective staples of this kind of character.

Martial arts training, possibly with weapons is also effective and plausible with most speedster designs. Thrown weapons are really good choices, letting you keep your distance.

Playing a Speedster

Speedsters tend to go first and often and rely on tactical advantages and movement. Players should be very familiar with GURPS Combat and able to think fast before considering playing a speedster. No one wants to wait for their turn while you stop everything to figure out your actions. The player of a speedster thus should be prepared ahead of time and constantly paying attention to the battlefield.

Speedsters can often get to a fight faster than the rest of the team so need to have good ways to survive or reasons for delaying.  The rest of the table will generally not appreciate being left out of every fight either. On the other hand a speedster that can transport the whole party can really be an asset! 

Being the groups transporter can be very expensive but here are some ideas.

Warp or Permeation with Tunneling.

Enhanced Move or other movement power with Affects Others, +50% can carry one extra person per level of Affects Others. Optionally a group can be carried by encasing them in a Forcefield with Area Effect and just one level of Affects Others.  The latter is called out for defensive powers so may not be allowed by your GM, though many will as its a "keep the group together" power and not so effective in most combat situations.

Simply being able to carry a lot is another options, use Payload, Can Carry, Extra Carrying Capacity, or simply high ST to do this. This is generally very expensive for a whole group though.

Optionally some speedsters may invest in a vehicle to haul their friends around.

Summary

Many teams will get by without a speedster, but most have one. I have played in campaigns where every PC was a speedster with different special effects and abilities. Speedsters can be very versatile so don't limit yourself to just buying up DX and Move!