You can always request a refund while outside the 2 hour limit, it's just going to be manually reviewed instead of automatic.
The time limit is arbitrary. There are lots of games that can be finished within a few hours. I've heard some devs say their short games are refunded at much higher rates than longer ones and recommend ensuring a game is at least 2 hours long. It's like YouTube paying more money to creators who make videos that are 10min+. Now you have videos that could have been 2 minutes stretched out for meta reasons.
I doubt Blue Prince specifically tries to hide game mechanics for 2 hours to prevent people from refunding it. It's just a slow burn puzzle game.