I liked Looper well enough. I found I could see where things were going pretty early on, though. It delivered as an entertaining sci-fi film, I thought.
In terms of seeing things early on, I have to say that I appreciated a few of the things they managed to disguise. None of the trailers or pre-release discussion hinted at the
other major sci-fi element in the movie, and it was mentioned kind of casually early enough and then moved to the background that just as I was starting to question if there was going to be a point to it, it came back full force and had me genuinely wondering if the time travel element was the feint and Johnson had secretly been doing a stealth
Akira update all along or something crazy like that.
I really enjoyed the whole diner scene where the Willis version tries to blow off the time travel logic questions but then gets yanked back into trying to explain it, which I thought was a fun way of tackling the "either you accept this premise or you don't" issue. Plus the sequence at the end of that section where Young Joe helps the mob chase Old Joe, then the mob and Young Joe both realize that the mob should also be after Young Joe was a perfect, Daffy Duck-style time traveling hitman gag.