YES! YES! YES! YES! :D

Instant buy (even though I already have it)! Any more adventure games in store for us?
Edit: Whatever the guy above said! :D

Wow, I was contemplating whether or not to buy it from their website (they had a 1 and 2 pack) for sale. Looks like my choice has been made. Thanks so much GoG!

Does it use ScummVM?

Probably DOSBox, but you can use ScummVM with it anyway, if you like.

I know, just wondering if they included it by default. It's probably the best method for playing SCUMM games.

Adventure games! What a pleasantly understated sequence of surprises!

Can i enabled subtitles in game?

OMFG YES

Very complex answer. and how did it?

Uhm... first DOSBox, then ScummVM, the next will be... MAME? :-P
Well, I'm starting to think that emulation could be a real deal here, contrariwise to what I was thinking about it before....
Ok, here's the truth: if you manage to get a legal ROM for Capcom's Ghosts'n Goblins on your catalogue I'll print flyers for you and I'll attach them to every wall of the city I live in :-P

Well, I can't help with Ghouls and Goblins (that's a CPS2 system, if I'm not mistaken), but I am the proud owner of a Neo Geo Pro Gear Spec cabinet with PuzzleBobble, King of Fighters 98 and a couple other games :)
Anyway, ScummVM isn't an emulator (DOSBox on the other hand is), but a reimplementation of various scripting utility interpreters. Kind of like a Javascript interpreter.
And it's definitely the best way to play these games for a couple of reasons:
1. Because it doesn't have to emulate a computer, it's very, very fast. Fast enough to play practically any game you throw at it on my 200Mhz Tapwave Zodiac.
2. Because it re-implements the game mechanics, the implementation can actually differ from the original game. For example, while most of the ScummVM games used a form for ADPCM encoding (very simple compression) for speech when they were released, ScummVM can also play them if the samples have been replaced with OGG or MP3 encoded ones. Or movies in MPEG-2 instead of Bink.
So, I'd definitely vote for including ScummVM. In fact, I'm gonna put my money where my mouth is and buy Simon the Sorcerer (although I already own it twice) whenever I hear about it being available bundles with ScummVM.

Is GOG going to give credit where credit is due, then? If they really bundle it with ScummVM and run the game that way, should there not be a mention of this somewhere? And the same with DOSBox.
Come one, GOG! It's even a powerful sales argument, given the number of platforms ScummVM is available on. "For just $5.99 you can own Simon The Sorcerer, which you can then play on your Windows/Linux PC, Mac, PS2, PSP, GP2X, iPhone, Amiga, Sega Dreamcast, Gamecube, Wii, any goddamn platform you want!"
[EDIT]
I just now saw this: http://www.gog.com/en/thanks/
How did I find it? Via a link on the ScummVM forum. I certainly would have never stumbled across it by accident. That tiny, grey "Our Thanks" link at the bottom of the page is hardly an eye-grabber. I think it'd be more suitable if you mentioned on the details page for a game, if it used DOSBox or ScummVM.
Other than that, keep up the good work! :-D