Bioshock Infinite

Guys, I have something troubling me and I hope I can find the answer here. I could have sworn I have played a partial demo of bioshock infinite around the mid to end of last year. I remember seeing old school planes, fireballs and these huge canons while riding or sliding on rails that connect each city together and seeing the city in the sky. When I was playing there were explosions going around, people fighting with each other and I think I started with some sort of shotgun. And as far as I remember when I jumped the city's edge of course I fell to my death into the ocean

Please say I am not losing it and that there was a demo or partial demo of this game on PS3 last year. That or they had a spoiler in game stop.

Whoa,,, there's no such game, id seek some help.

Me joke, yes there was a demo available.

No seriously, it was playable at the time. The crowd was very small(the ones that were fighting each other) everyone in the city was tearing each other apart, people acting as if they had gone mad. In fact you could control what you were doing. It was a big open area and you were shooting anyone who had posed a threat to you. I could never figure out though how to stay on the rails to cross over to the next city I kept falling off to my death.

It was first person shooter and I was playing as some guy who had just woken up from being knocked out. I think they when I tried jumping on the rails the camera switched to 3rd person, but my mind is still a bit hazey.