The entire appeal of an idle game is to sit back and let the game run in the background without needing you to be there the entire time. This game completely runs against this idea by requiring you at the screen every minute to complete and select the next level. Other idle games give players the ability to click for more numbers or provide some sort of contribution if they do spend more time on the game instead of idling but this game gives no such option.
It would have been better to have each level run continuously rather than a limit on the number of enemies to give the player more time to idle around instead of sitting by the screen with no ability to contribute.