The Spy Hunter dump has been patched to fix the bug which allows you to drive
to the right edge of the screen to avoid collisions. A video demonstrating
this bug can be viewed here: https://www.youtube.com/watch?v=-gSnoA9FvMc

The LDA $4D89 instruction at $1A18 in the dump file (at address $9A18 when
loaded) has been changed to:

JSR $BFF5

A small routine has been added at $BFF5 (at $3FF5 in the cartridge
dump itself) which adds an additional check to the value held at $4DB9
in order to correctly adjust the original value loaded from $4D89:

LDA $4DB9
CMP #$23
LDA $4D89
ADC #$00
RTS

Many thanks to TNT for providing the original fix.