While two stat points are easily obtainable on the Philadelphia level in Tony Hawk’s Pro Skater 1 + 2, there are a further two that might elude you.
To get the two hidden stat points in the Philadelphia level of Tony Hawk’s Pro Skater 1 + 2, you need to open up its secret area. To do that, head to the left hand side of the main area from where you start, and try to find a circular building with a small set of steps leading up to it. A blue rail surrounds it. Use the picture below for reference.
Some kind of cable is connected to the blue rail, and if you grind it, moving towards the pole, you’ll trigger an incident. Two poles will fall over destroying the fence that confines you. A new area is then opened up for you to explore, in which you’ll find a further two stat points. One is at the far end, and the other is on the left hand side.