Make sure the Auto-Aim feature is checked in your game options; that may help the excessive dying. Two other helpful tactics are: binding a rock behind yourself in energy form to block attackers' shots while still allowing your own to pass through, and also not underestimating the potential of your Shield. Shield can deflect most shots in the game, and if you maintain it with the hotkey*, you can keep it up indefinitely.
In terms of unclear goals, well, that is a problem if you need clear objectives all the time. There is never a place aside from boss fights where you get locked in or stuck, though. You can back out of the Energy Temple at pretty much any point.
I don't know about the drifting part, there's a few things it could be. There's current, and that's supposed to be annoying and counterproductive. It could be mouse problems like you said (sometimes it's the mouse drivers that are screwy and not which mouse you're using). Also, Naija drifts for a little bit due to momentum after you stop telling her to move forward. This can be problematic if you're in a tight spot and need to sing, since you can't sing and swim at the same time, but you will still drift when you stop to sing.
*You may find the hotkeys useful: they are the number keys 1 through 0. 2 will put you in energy form, 9 and 0 are shield and bind (I forget which is which).