Is the demo deck on the main page for this game still vialble or was it pre LCG ? I am just curious about how this game plays, not a Cthulhu fan so not really sure if I would like it but if the game play is good.

The demo deck is actually even from before the CCG version launched. Some cards got some tweaks in the final product. Still, you could concider them 'viable' if you want to find out how the game plays, even though some cards in it aren't current anymore. At the very least you'll get a taste of how a game plays. Keep in mind you're only playing the 'demo version' though. If you're into card games/board games, you'll probably like what you see, and maybe even surprised on how much you recognize and how much you know about the universe.

But it'll kinda be like seeing a picture of a blind date that's ten years out of date.

You'll learn mechanics, but are viewing the first 30 (and some pre-firsts as Marius said) or so of 1,700 cards. Most of the glamour / awesome colorful characters and mechanics was yet to come.

Where have you gone Gentleman Duelist?