Just saw it, too. I knew how badly it was regarded, that there was no Mars (weird) so I figured I'd be happy just to see mindless blow-em-up popcorn, and that's exactly what I got. Waiting for movies to come out on streaming or DVD really solves a lot of the problem of being disappointed since I know exactly what I'm in for.
The major issue was the lack of any dramatic tension in the "is it real" idea. There's no reason this iteration needed to follow the Ahnold movie or the PK Dick story, so they could have done better with that. I was halfway hoping it really was all a Rekall fantasy. Although that would have been an aggravating plot twist, at least it wouldn't have been 100% expected.
The Fall was one of the loopier sci fi ideas I've seen lately. So there's really no more cost-effective way to get from Australia to Europe other than by going through the planet's core? I also enjoyed the way Our Heroes were scrambling around on (apparently) the outside of the vehicle, with no regards to heat or the incredible speeds that sucker must have been travelling at. And for that matter, why have workers commute from Australia to build robots when you could build the robots in Australia and ship them to Europe in a more space-efficient manner than humans would tolerate? But such quibbles violate the principle of watching a movie like this, which is just a notch above a SyFy Saturday night monster movie.
Next up: Looper
! I expect that one to be much better.