$1E is the number of rooms in total.
Every room uses the same tiles for the walls, floor and ceiling.
The floor test code is hardcoded to only accept bright red and bright cyan as solid items that Wally can stand on.
$20 is the number of objects in total.
Each object has its own percentage score which is added when picked up.
The congratulations message calls the next game 'Life of Wally' but of course we know it becomes 'Everyone;s a Wally'.