re-attach battery driven gamepad to PC power supply
You don't want to use a simple resistor to drop your voltage because this is very dependent on current draw.  And your controller is drawing varying amounts of current, depending on which buttons are pressed, and LEDs, etc.

For example, the controller might be drawing 60 mA when idle, but much more when active.  If it draws more, this will cause the resistor to drop more voltage, and the circuit could starve.

What you want it to use a voltage regulator that outputs what you need.  To use the same family of parts that you are currently using, try a MCP1702-1502 instead of your MCP1702-3302.

If it turns out that the device uses more than 200 mA, perhaps if it vibrates (?), then even the MCP1702 won't be able to provide enough current.