Thank you for the feedbacks!
Regarding the gesture idea, that's something we thought about but didn't want to do in the end. The reason is that the game can get really fast paced at high levels and we wanted to prioritize input efficiency, even if it can be a bit unintuitive at first.
About the difficulty, we realized after publishing the demo that the game was actually way easier than expected and we're going to rebalance that to provide a more challenging experience.
Thanks again for sharing your thoughts, it's always appreciated.