Some info I've gleaned, mostly from the unofficial wiki:
From
Pramas's interview we know that the core mechanic is 3d6+Modifier (which is not the most inspired mechanic, but is at least very conceptually simple for an introductory game). Also, the starter set will only cover levels 1-5 (which I think is pretty nice, assuming the next set, levels 6-10, comes out reasonably quickly).
It will feature the same 3 classes as the game: warrior, rogue, and mage. In the video game, you can get a
specialization at around level 7, which is like a prestige class/paragon path, a sort of sub-class. Presumably, these would be a major focus of the second RPG set (levels 6-10)?
The video game will feature
6 attributes: Strength, Cunning, Magic, Constitution, Dexterity, Willpower. The first three are closely linked to the three classes (Strength for warriors, Cunning for rogues, Magic for mages). The second three seem more general-purpose, and I speculate more defensive. Attributes start at 10, plus race and class bonus, plus 5 points to distribute at character creation, plus 3 per level up. I'm not sure how much of this will be preserved in the RPG.
There are also
skills (available to everyone) and
talents (exclusive to warriors and rogues) and
spells (exclusive to mages). They all work the same way: They are either passive (always on), sustained (you turn it on and off), or activated (you use it as an action). From the list on the wiki, skills tend to be passive (or activated, with passive upgrades); spells tend to be activated (a few are sustained); and talents are a mix. Skills/talents/spells don't seem to have levels, but are binary, like feats (you either have it or you don't). However, some have prerequsites, for example each skill has an "Improved," "Expert," and "Master" level that you can get after getting the basic skill. (I think they should have called them "Basic," "Expert," "Companion," and "Master."

) I have no idea how any of this will translate to the RPG. Pramas that spells will use magic points/mana, but I haven't heard about talents and whether they use any sort of points.
In the video game the computer can perform very elaborate and precise calculations. So a mechanic like "Each point of Strength adds 2.5% to damage with melee weapons, or 3.5% on a two-handed weapon" might be great for game balance in the video game but would not work at all in the PnP RPG. So, it's really hard to know what the core mechanic might be like based on info about the video game: 3d6+Modifier, where +Modifier might include attribute, some derivative of attribute (ala D&D), level, skill/talent/spell bonus, equipment bonus, class bonus, who knows.
-- 77IM