So what exactly are the buttons?

[hideinlight]

I press ctrl + Q, the menu pops up.
Can go up and down, but there's no indication on which button I should press to actually choose the option.

[DrBeef]

You can use RETURN, however as that can interfere with the game, you can also use RSHIFT (right shift).

If it isn't in the documentation already, I'll add it.

EDIT: It was already in the documentation... in the section titled "Vireio Perception - Shortcut Keys"

[hideinlight]

I see it now, but it's way to hidden in the instruction manual and knowing they key layout is one of the most important bits of information.
Might I suggest, including a small PDF, specially just for the shortcut keys in the Perception/instructions folder, something that doesn't require access to the net and that's immediately visible. When people still bought boxed copies of games they always included a separate piece of paper showing the basic controls, especially when they had extensive manuals.

[DrBeef]

That is a fine idea. I shall see if I can get it in ready for the next release (imminent..)