Ask HN: Which pricing model would you recommend for a Puzzle Game?

Hello, I am making a mobile puzzle game where players use a very simple programming language to solve levels. The target audience is people who like challenging puzzles even if they are not programmers.

I am thinking of two options for the pricing model. 1. Paid app (something like $2.99) 2. Free app with a single iAP to unblock the advanced levels ($2.99 too). There will be a lot of free levels, but the advanced levels have additional elements non available in free levels.

Also, I am well aware the many people here don’t like the pay-to-win model. But because of the nature of the game, some users will be stuck for a long time and may abandon the game. So I am thinking of introducing an iAP to access the solution of a single level. It’s a paid feature in order to encourage players to find the solutions themselves.

Which pricing model would you recommend? And what do you think about offering solutions with iAP?