Strictly speaking, you shouldn't be using the key codes
for the cursor keys explicitly. Instead you should use the
kernel function MapKeyToDir. This gets you two advantages:
1. No assumptions about the used keyboard driver
(Sierra SCI had keyboard drivers for Tandy keyboards as
well as the usual ones, which probably mapped these keys
differently. FreeSCI always returns the usual mappings.)
2. Instant support for joysticks.
Nowadays, (2) is the most important point, of course.