I'm sure you have heard this but you need an end game be it a prestige or a new game+ you need something there it's so good just unfortuately comes to a rather abrupt end
I really wish that there was a total cash per sec stat somewhere also some form of a challenge mode would be great. Oh and of course and endgame! lol. Love the game guys keep improving :)
Was it after using a skill by any chance? If so, they are bugged. New version of the game will be uploaded very soon.