1) The board is gunked up pretty good. May not be an issue, but... it lacks style.
2) The alignment of the TQFP package is quite a bit off. Who knows what's going on underneath.
3) If the chip gets hot instantly and can't be programmed anymore, it's probably dead. I've killed one or two myself by accidentally applying over-voltage (about 12V).
4) If you redesign it anyway, add the FET pull-down resistor. Otherwise it might switch on willy-nilly.
I agree, there is a lot of flux on there. I have encountered problems before with flux being conductive.
I also agree about the chip placement. That definitely could be the problem.
I also agree with needing the pull-down resistor. With nothing attached to the gate, the internal leakage current will slowly charge it up. You will get a fet that is only partially turned on, and it may cause overcurrent problems, or it may overheat and burn up.