I played the demo and love it. Getting the $20 credit is an amazing add-on :) If you doubt the game, play the demo. They even let you mess around with crafting guns and your suit so you can get a taste of that.
Same here man! XD It's short and you don't see anything that hasn't already been in vids, but it still gives you a good feel for it. I really dig the new crafting system. I think I spent more time on that than the demo was long. Two minor issues I had were with the more traditional, bullet firing guns (they just didn't feel that great to me) and I couldn't figure out how to take cover (I'm on the PS3).
I really nerd out on crafting/customizing weapons in games (the "gunsmith" mode in Ghost Recon: Future Soldier is another relatively recent weapon modding tool I'm quite fond of). XD I didn't realize a demo was up for MG: R. Thanks for the heads up! XD I'll definitely have to check it out.
nice to see Amazon trying to match Best Buy's credits, but remember that without places like Best Buy discounting their games Amazon wouldn't give us anything like this, they're just hyper competitive cheapskates. if you value market competition and want to continue getting $20 credits then buy at Best Buy if you can.