Needs to not delete lines when you just go over them, without letting go, and if I drop purple and pick it up immediately it should only count as 1 move. Those small annoyances don't make the game harder, they make it easier to rage quit.
Maybe add a pinball minigame, "Ping-ball". Make it maybe $100, with 3 lifes, and objectives (hit target, enter hole, re-enter) that earn money per completion.
2% interest, after x seconds, and only if I don't deposit or withdraw any money in the given time. It needs either higher interest rates or the ability to add money without restarting the timer.
 "Stream Master Unlimited"){kind=icon}
 "Pingy the Ping Idle RPG"){kind=icon}