Packed tight
One instruction added to the first routine.
8E02
message printer
—
8E4B
score display
↓
8E7D
sound effects
↓
8EC2
ant update
↓
every later address shifts by one,
and every CALL to them is now wrong
Parked on boundaries
The same instruction added, with slack after each routine.
8E00
message printer
—
· · · slack · · ·
8E80
score display
✓
8F00
sound effects
✓
8F80
ant update
✓
the extra byte lands in the slack,
so nothing downstream moves at all