Thanks a lot for the feedback :)
To progress to a new level you need the corresponding amount of pumpkins displayed (or more) and the money displayed. Then you just press the reset button. Now that you mention it, I probably should have made that a bit more clear, simply just adding a text that said "Requirements" would probably have helped a lot.
Also, the game automatically saves once every minute so you can easily get back in whenever you feel like it ;)