There are a few glitches to watch out for in Primal.
The most serious glitch is the "falling out of the world" bug. This can be quite entertaining for a while, as you wander around peeking into all those interesting places you shouldn't be. However, you can't get back in the world! If this happens to you, the options are:
Don't save while stuck here, or you will still be stuck outside the world when you reload. Save frequently to keep yourself from becoming permanently stuck.
The following algorithm (when Jen follows Scree or vice versa) is sometimes quite poor. It's not unusual to have to go and fetch one or other character. Keep track of where the following character is and you should be fine.
Other known bugs are graphical glitches (disappearing textures and the like), sounds that cut off half way through, and the fact that many actions take a an inordinate amount of time (e.g. opening doors, draining energy).