Very nice art style, and also crazy for your first game.
2 small remarks tho:
1: a small rounding error (I think its one not 100% sure) but you need 1 more cash than the reauired amount (so for 20 you need 21), and it also doesn't update automaticly (so when you buy it, it doesn't show your money decreasing).
Thats a very small problem, that's very easy to fix, and it happens.
2: the bus only appears when buying an upgrade (to hide the assets changing, thats a very good way to hide it) but it could maybe also appear on a set scedule, (every 10 seconds for example) and upgrades appear when the bus appears on the scedule.
Don't take this the wrong way, I really enjoyed playing your game and I hope you will continue making games, as this is already pretty good for your first game. (mine are way worse). I just write way to mutch, as I like fully explaining myself.
Goodluck on your next projects.