I finished Level 41: "Tower Ascent"! This is a very short level that presents a jumping challenge.
I checked my updated plan: it has 60 levels total. So how much is that? They vary so much in length that time may be a better gauge.
Knowing exactly where to go and what to do, I can beat the "shareware version" (first 12 levels) in an hour. The paid version quintuples that.
Five hours for the dev to finish the game sounds good?