How does one gain levels (and thus character points). Is this an XP system (e.g., D&D), or do you get better at skills you use (e.g., RuneQuest), or some other combination?
ERP bases Advancement on two types of experience point (XP) scores: Victory Points and Role-Playing Points. In order to advance in level, each character must earn the requisite number of Victory Points and Role-Playing Points. Having gained a new level, a hero earns Character Points, which are the currency of character advancement, used to buy or improve abilities. You earn Victory Points by defeating monsters or escaping dangerous situations. You earn Role-Playing Points when playing your character concept well, or by coming up with fun, good ideas that further the story.
To advance to the next level of experience, a
character must achieve two things:
1. Victory points equal to the character’s current
level of experience.
2. One hundred Role-Playing Points, representing
100% capability within the current level of
And yes, there are simple rules in place for when characters have enough VPs, but not enough RPs, or the reverse (Excess Points is a third category of XP, used as a game balance mechanic). For example, 100 excess points (which are overflow RPs) convert to 1 VP, if the character doesn't have enough VP to advance a level. Also, each excess VP convert to 20 RPs. So, low levels adventurers tend to advance quickly by means of VPs (combat and danger), but at higher levels, they depend more on RPs (thinking and story interaction).
How does ERP guide/restrict skill advancement? For example, you play several sessions in a desert, but a PC wants to advance his swimming skill. Can he automatically do this when he gets his character points?
From the core rules: "For each level of advancement, a player character cannot purchase more than one increase to an ability’s rank value, including Specialization or Mastery dice. In other words, a character may move an existing ability up from D4 to D6, but not from D4 to D8 for a single level of advancement. However, he can purchase any number of new abilities, including Specializations and Masteries". The GM may determine whether a character has access to the sort of training environment needed to add a new ability, specialization, or mastery.
How does 'occupation' (from quote above) help guide advancement?
Occupation is a guide for players and GMs in deciding what assortments of abilities are well suited to the campaign world. The ones given in the core rules are geared for your classic epic fantasy setting. They serve as templates.