Criticize SMPS PCB Design
My first thoughts:


The MOSFET you've chosen is overkill. A 35V output application will not need a 500V MOSFET. Try something in the 100-150V range, which will have lower gate charge and \$R_{DS(on)}\$.
The boost diode should be a hyperfast rectifier with soft recovery characteristics. These are most commonly found in high-voltage (>500V) ratings for use in PFC, but may still be useful. Consider 'stealth' diodes from Fairchild or 'FRED' diodes from Vishay. (Soft recovery and hyperfast are most useful when the converter is operating in continuous mode.)
You should have a fuse on Vin. There isn't a way to isolate input from output in the event of a fault without one.