just uploaded a new version (V0.50d) that contains a bug fix for this issue (hopefully)
it would be pretty tough i think. i actually at one point had additional denominations of chips working ($10, 25, 50, 100), which is how paying off the debt in the time limit would be made possible. But unfortunately right now most code in the game assumes that the value of each chip is $5. I do hope to get that updated sometime in the next couple of weeks though