Very neat idea and very intuitive once you look at the tablet screen. Moving the gems around feels a little clumsy, but it's very tactile and feels deliberate. Would have appreciated some feedback for when I hit an enemy. Was hard to tell if I was missing my shots or if they just had more health.
Being able to assign gems to a default location on pickup like health or ammo would have been really helpful.
Also cool that you can straight up remove elements like sfx and music. Unsure if I would like it in a fully released game since it gives an advantage to removing music, but it got a chuckle out of me that I could get an extra bullet if I didn't mind silence.