I wish I could love The Platform, but it felt a little bit too red anvilish, if that makes sense. As far as thrillers go, Snowpiercer has a similar message while not being exactly subtle.

Edit: I just reread this comment and it sounds like I'm saying The Platform is too subtle, haha. What I mean is that The Platform kind of works against itself by having such a highly abstracted setting that exists basically just to make a fairly simple statement. It's cool, and I dig the Kafkaesque sort of style, but I feel the plot and characters of the movie weren't focused on enough.