So I downloaded and installed Steep, and it looks like it took a bit more than 18 gb of space on the hard drive. I have almost 90 gb left from my 2 terabyte drive (Yes, I have a lot of games installed).

And yet, despite having more than 4 times the amount of space available than the full game takes up, it won't let me play because "there is not enough free space in system storage." So my question is, what exactly is that requirement? And more importantly, WHY? Why on earth does a <20gb game seemingly require so much hdd space to run?