The review has more footage.
I think some of it is just bad grading of a camera that's not even running final firmware.
People don't yet know the right gamma settings, etc. Canon Log 3 is probably coming later on and it should improve things as well.
The Sigma fp had exactly the same problem, you can look at DSLR video shooter's initial impression video, it really depends on what settings are used in Davinci Resolve for the footage.