I didn't like the theme changing colours throughout the game, it made text unreadable at times. Some automation for Particles > Sparks would be good. Having to type in the increment amounts should be replaced with buttons (e.g. 10%, 50%, Max) or sliders, also the amount seems to reset when you switch pages. Progression is good but maybe show the next upgrade sooner, instead of it being so close to when you can afford it.