Hey since you can't play them I have an idea. Try this site: http://mobile.gamezone.com/gzreviews/r17853.htm (this one in particular reviews GnG)
Anyways, that place reviews everything basically that plays a game for the most part. They're VERY critical on things sucking hard on mobiles, and they will link other sites that give scores so you can get opinions and work up averages.
As far as GnG goes, it does NOT have all the stages of the arcade, just 1/2 of them. On a standard phone pad 1/2 is down or duck, 4/5 left and right, 7/8 are your ups, and then the other 3 (forget which) are shoot and jump (one doubles down.) There is music on it, just the original GnG stage 1 tune though if I recall (haven't seriously played it in a bit.) And the visuals are closer to the arcade than the NES, but they're a hybrid for sure. The challenge is still a bitch, and not so much due to the control which will take a few moments obviously to get used to.
Double Dragon, like GnG has less stages, and I think there's just 4. If I recall it's stage 1, 2, another, and the final. They're about the same size if not completely there (been a long time since I did arcade DD.) In that one it has all the musics from the various stages and SFX too. Now I am not sure if it's a limit of my phone as it was a fairly new freebie 18mo ago, but you can only have one or the other, or mute it. Controls, the nub moves you, and as stated in the other post, each button has it's own function. There is a great test bin area where you can try out the controls on a dummy after reading them to get comfy. It's a fair challenge, and I do mean as fair as the original was in trying to get behind you and kick your ass from 2 sides.
Another I know to be quite good but I never plunked down on it are the BONK games, faithful conversions of the TG16 originals and control very well apparently too. I'd also personally love to get Ms or just original Pac-Man, but those cheap fuckers at Namco want me to pay $3/mo for it whereas every other company on the Sprint line has a monthly AND permanent access (twice the price, so $6, sometimes $5) charge too. I'm not paying $3/mo for pac-man.