I think it could even stay as a lose condition of you tweak the numbers. Discovering it can go into negatives was fun, so having to balance it between two fail states could be an idea to consider. Alternatively it can negatively affect other processes so you have to constantly get rid of it.
Oh, one other feedback: the reset needs to be communicated more clearly, I've often found myself realizing stuff had reset after a long time starting at a screen. Preferably a summary screen showing how much you got at reset and a button to start another loop.