Pathfinder SRD is a D&D system that is based off D&D version 3.5. Set in the traditional fantasy world of Gnomes, Elves and Dwarves along with the traditional class options of Fighter, Mage and Rouge, Pathfinder is about as traditional as it gets. Pathfinder also has a space variant, but we haven’t tried it out since it doesn’t look that different from regular Pathfinder, as even the gear only seems to have been given a fresh coat of paint as opposed to drastically changing anything.
Much like the game it is based off Pathfinder operates around 6 primary stats, a class of your choosing, which combined with your stats will determine your bonus to hit and defences. You have armour class which traditional attackers (swords, bows etc) have to try to get past with their attack bonus, and then you have magic, which will affect one of your three saves (Reflex, Fortitude and Will), and you will have to try to get over the save DC of the spell. All in all, it is a system anyone who has played any Wizards of the Coast D&D version should be familiar with.
The most important part of any good D&D game is of course the copious amounts of loot, and Pathfinder has a decent selection of loot. While the loot isn’t the most inspired in the world, there are a few pieces that are more unique than others, such as the Merfolk belt, which as the name suggests, transforms you into one of the Mer once a day, and the large amounts of loot described are plenty to keep any party afloat.
Another important part of any good D&D based fantasy system in my opinion is how well designed the magic system is, and for Pathfinder, well, it’s a bit iffy at times. On a note, if you want to avoid a long discussion of why the magic system is broken at higher levels, just take away that lower level spells are useless at high levels because of math.
Long discussion of math and magic, read at your own risk. The main problem we’ve found is spell DC, which is a combination of the casters main casting attribute modifier (so (X-10)/2, with X being the original stat), a base of 10, and the spell’s level, leaving an equation that looks like 10 + spell level + stat modifier, the main problem with this is that lower level spells become completely ineffectual at higher levels. While generally this isn’t a massive problem, as higher level spells as a rule of thumb deal more damage. The problem comes when you use metamagic, think of it as putting your magic on steroids, it’s suddenly a lot stronger, however the use of metamagic comes at a cost, when using metamagic your spell counts as a spell from a higher level, however, it doesn’t count as a higher level spell in relation to spell DC. This means that while your level 1 spell might be powerful enough to slay a god (I don’t know what you did, but let’s say it is), what this means is that your spell DC equation looks like 10 + 1 + stat modifier, the problem with this, you are never going to hit that god with your spell unless they roll a 1 on their save, meaning that it is virtually worthless, especially since it is now taking up a higher level spell slot, meaning that you’ve had to give up a use of a higher level spell that might have hit that same god.
Overall, while Pathfinder doesn’t push the boundaries of D&D, it is a great system to introduce D&D to new players, and has a lot of replayability due to the variety of classes offered, along with the flexibility of the system, making it in my opinion one of the better D&D system out there.
We’ve done a lot of experimentation with Pathfinder’s flexibility, and found it to be pretty compatible with just about anything, for example we’ve allowed for other systems to be used at the same time as Pathfinder in our adventures, for example, we allowed Monty Cook’s Arcana Evolved series to be used alongside Pathfinder to allow for some variety. Along with that we’ve also used books like Liches – The Lords of the Night and Vampires – The Lords of the Night. We’ve also tried things like gestalting, which is levelling up two classes at the same time on one character, and ended up going all the way to hexastalts, so six classes on one character, which was based off us looking up whether anyone had discussed one character having that many classes, and simply went with it when we couldn’t find any search results (though there was a forum post discussing hexastalts, so we might have to go up to heptastalts).
You can the Pathfinder website here