Thanks man!
Yeah, I mean there are different reasons for that. A good example would be when a game developer on Reddit reviewed my game in r/playmygame. He played it for 20 minutes on stream and told me he genuinely thought it was the best itch.io game he'd ever played. But then he also said it was too hard for him. When I watched the footage of him playing my game, he didn't fully read the How to Play screen and then he even skipped over the Flash Shield tutorial. And so even when he was playing on Practice difficulty, he could not make it past Waluculican (the wasp mini-boss) because he wasn't using the Flash Shield.
But that being said, some people just aren't accustomed to shooters. And if you aren't accustomed to shooters, you're probably going to find the game to be very un-intuitive and won't fully realize how useful the Flash Shield is because you're just so concerned about staying alive more than anything else. For some, they just weren't paying attention, and for others, the important things just didn't 'click' into place for them and changed their experience with the game as a result.