Pathfinder 2E Playtest Rulebook
The Modes
We are introduced to something that has always been there but is now being defined. Three modes: Encounter, Exploration, and Downtime.
Encounter is typically combat. Exploration is typically Travel. Downtime has been most characterized by spell replenishment. Not only Pathfinder but also DND has had all three modes. Fantasy books have these modes; these are story modes.
The fact that these modes are being defined point to a higher level of organization in 2E and that's good news.
Simpler Actions per Round
A simplification:
1 round = 3 actions and 1 reaction.
A character may use any number of free actions even in another character's round.
A round, as before, comprises 6 seconds of an encounter.
In 1E one round was one standard action, one move action (replaceable with a standard action). 1 quick action and several free action. Or scrap everything and just do 1 full round action. Now it's simpler: 3 actions, 1 reaction. Free actions anytime.
Tasks that take multiple actions to complete are called Activities. The game provides for 2-action and 3-action activities.
The d20 roll
As usual 20 is a critical success and 1 is a critical fail. But . . .
Rolling 10 higher than DC is now also a critical success and rolling 10 lower than DC is now also a critical failure.
Proficiencies
In real life, like for your job you're either unqualified, qualified, or overqualified. That's your proficiency.
Pathfinder measures your PCs proficiency against equipment, weapons and the like. The levels are untrained, trained, expert, master and legendary. Of course Pathfinder can't leave it like that. There has to be a kind of numerical equivalents for these proficiencies. But first we need a baseline. The baseline is your PC level. Untrained is Level -2, Trained is equal to Level, expert is Level + 1, Master is Level + 2 and Legendary is Level + 3.