The Geordie boss watched his side take the lead after a thumping goal from Jonjo Shelvey in the first half but two penalties from Paul Gallagher secured North End's first win of any sort against Newcastle since 1979.
Bruce reflected: "There were a lot of positives out there considering I changed the team.
"With VAR the game is changing direction and with the handball situation. It is becoming a lottery if we are not careful.
"There could be a lot of big games decided on whether it is handball or not.
"What is clear is that if it hits you on the hand it will be a penalty. That is as clear as mud. There will be some controversial decisions which will upset everybody. We have been given two shocking decisions.
"Let's just hope they are out of the road for us now."