Free-to-play requires ads

I jumped at the chance thinking 'These gems for a 15-min daily quest are amazing!', but it took me over 30 minutes to clear hidden quest level 10. You really have to use your brain because things like missing screws or plates blocking screw holes can get you stuck. Unfortunately, some stages simply don't have enough holes to insert screws, so free-to-play players have no choice but to use precious items or watch ads to clear them. It completely kills the mood when you're trying to strategize. I'll continue if the next daily quest also has high rewards, but if it drops to three digits, I'm done.