It may be worth it if it doesn't slow it down to much. An alternate control scheme would be to be able to rotate the direction in which you fire, like the PC game (with the ability to quickly jump to any multiple of 45 degrees for convenience)

The only problem I can think of with muli key press is that either there would have to be a delay in the portal shoot (since both keys might not be pressed at *exactly* the same time) or launch the portal upon release of a key, not a launch

and as for the variable angle idea, the reason I am hesitent is because you often times need to be able to shoot portals quickly in mid air and indont want there to be too long of an aiming time

That means that you lose fideliy in the air then tho right?

perhaps have a line emanating from the character constantly, showing where the next portal is going? the keypad would function as usual, so no matter where the line is pointing, if you press 8 the line jumps to 0 degrees, or pointing upwards. then you could press the addition button to make it move a little clockwise, and subtraction counterclockwise? or use the paranthesis buttons to control counter/clockwise.

new-ish idea:

you have a line that controls where your next portal goes.
( = move counterclockwise couple degrees
) = move clockwise couple degrees.
1-9 = move to corresponding angle and auto-fire a portal.
? = fire portal

I think it is fine as it is, but it wouldn't hurt to try 22.5 accuracy

Yeah I have decided to implement 22.5 degree accracy and see how it feels.  If the delay is noticable or no good then I can simply switch back.  Most of the time anyway you only need 45 degree, adding anything more than 22.5 I think would be overly ecxessive.   What's nice is that you can keep one hand on the arrow keys and one hand on the numpad, with the occasional [2nd] to grab a box.  So we shall see how it works implementing 22.5 then!   

Well I currently am getting a framerate of 33 frames per second so it's very probable that I may have to have a delay for multiple frames. I'll quickly test it out and if it's no good I will stick to 45, since it's intuitive and easy to use.