I thought the officiating was good - slightly in KC's favor, but none of the calls were egregious.
That helmet-to-helmet was incidental - the defender didn't lower his helmet. It was good technique.
The push against Kittle was a classic arm-extension push off, and created separation. I don't even know why that's controversial - that was a good & necessary call. It was not ticky tacky, as many are saying.
And I even see some fans complaining about the DPI in the endzone, when the defender didn't even turn around, saying the ball "wasn't catchable." It absolutely was if the guy wasn't all over the receiver.