Nice game, you could add some descriptions to the things you buy, and a goal to achieve. Also, you should try adjusting the escalation of prices, things are too cheap, and as you buy more expensive things the increase should be drastic enough for me to consider buying it instead of the cheaper versions, that way you wait and acumulate and when you use it all and see the numbers increase much faster you feel really satisfied.

if you use the roll button of the mouse the upgrade window goes down and hide.

pretty cool