Skills

Getting a good balance between too few skills and too many skills can be quite hard, especially when the definition of these limits varies from player to player.

Unless there's a good reason, Yags tries to keep similar skills which would realistically be all known by a particular type of character as a single skill. For example, Brawl covers punching, kicking, wrestling and dodging - few characters would be interested in learning only one of these and not others, and it's fairly realistic to bunch all such abilities together.

However, Science is a broad and complex subject. A character may want to be equally good at all sciences, but in a modern world this is rarely the case (low-tech skill sets for Yags actually use a Natural Philosophy skill, which does cover everything), so there are a number of specialist science based skills such as Physics, Biology and Chemistry.

Combat is actually one area that is quite heavily simplified - Melee weapon covers pretty much all melee weapons, including spears, shields, maces and swords. Traditionally, warriors did swap between types of weapons quite often, depending on the type of fight and how their opponent was armed and armoured. Many (not all) games actually force PCs to stick to a single weapon since they can only afford to put up a single skill.

This does lead to a problem - it prevents the sort of specialisation that can make some character types interesting. This is where Techniques come in.

Techniques

A technique is like a specialisation that can be taken with a skill. When a skill reaches a certain level, a technique can be purchased which either mitigates certain penalties, or allows the character to do something they wouldn't otherwise be able to do.

For example, Rifle allows a character to fire all sorts of rifles in all sorts of ways. When their skill reaches level 2, they can purchase the Quick load technique which enables them to reload a magazine as a free action. Other techniques reduce accuracy penalties when firing automatic bursts, or give greater bonuses when aiming.

Spaceship systems allows characters to operate a large spaceship, though by default they have experience with relatively small civilian craft, and suffer a penalty (their rolls are halved) if they try to operate larger or military vessels. Techniques enable them to specialise in other types of spacecraft, operating them without penalty.

Techniques can chain off each other, so lower level techniques must be learnt before higher level ones. A single skill may have multiple chains - for example, Brawl has a number of technique chains each related to a martial arts discipline. If you want to play a Thai Kick Boxing champion, then you can. Because everything comes off a single Brawl skill, you won't find yourself in the situation where a kick boxing champion is totally useless in a brawl where they can't kick.