In the original TTD, you could trigger an integer overflow by building a very long tunnel from one end of the world to the other, so that the billions of money subtracted got negative. ;)
I remember getting this bug on accident when I was a kid. I was building a tunnel, but clicked the wrong tile. It popped up a huuuge sum of money and I got scared that I messed up and I'll go bankrupt, only to realize I now had 2B dollars...
https://www.playdosgames.com/online/transport-tycoon/