Not bad, not bad. Don't agree with Béla that it's perfect, there are differences but it does look pretty close.
I think the brightening/defocus is either not picked up by the iphone or is still too low. HOWEVER I am comparing to my 25" Amplifone of which I still dont know if it is set up properly. when fire bolts start nearing on my machine they go out of focus. I am still not sure if this is meant to be. I -do- know that the concentric circles on the Deathstar explosion is supposed to defocus, but mine doesnt do that too much either.
I am still extremely happy with my picture though and so should you be, this looks a LOT better than standard MAME.
The POKEY sound sounds pretty good but the voice synth is indeed off. Remember that the screeching sound of the tie fighters is also produced by the voice synth.
Enjoy your game Giddy, it's totally enjoyable this way. One tip: don't fire in the trench scene until you are at the hole. This is "using the force" and gains a nice bonus....