C01F: 1A 50        ORCC #$50  Disable hardware interrupts

This is identical to $0000, which disabled all hardware interrupts (i.e. disabled all keyboard/joystick inputs). Nothing new there, but $0000 has just been run; the more interesting question is, why are we repeating it?

To me it suggests that this is a subroutine entry point which we'll jump back to later, from a point at which hardware interrupts are probably not disabled. If we search the code for $001f we see that this is true:

C3AB: 16 F6 E3     LBRA $001F   Branch to $001F

By running the game in the debugger, we can see that $001F is executed when:

1. We first turn on or reset the machine (via execution from $0000)
2. We start a new game by selecting a skill level from the start screen (via branching from $0939)