-Simple yet quite innovative and fun idea, the hardest kind of concept to acheive.
-Animations are really smooth and satisfying
-Progress is fast and engaging, never feels like farming, which is essential for a game with upgrades.
-Interface is wisely done, there is no upgrade cost indicator because you don't need to know such thing, there's only 4 upgrades and you earn more money quickly.
I don't think that it needs more upgrades, not every game needs to have months of playable content, maybe you would think that there's not much to decide and its too much about luck, you're not wrong but that's all that this game needs, however, this puts the game deep in the time killer category, and for me a 5/5 game is a game where you feel like you're challeging yourself but this is a gem nonetheless