Overflowing is actually not that hard in NetHack. Score gets rather meaningless in NetHack as killing monsters always yields the same number of score points.

So if you grind long enough, every high score is possible and overflowing the score counter with pudding farming was quite easy on 3.4.3 on 32 bit systems (the score counter is a long).

What players have done is a MAX_INT game or ascension. That needs some preparation and the MAX_INT game is easier to do than the ascension, as the ascension gives you additional score points, so you have to anticipate this.

There are even 64 bit MAX_INT ascensions, although those are done of course with exploiting some bugs.

https://nethackwiki.com/wiki/Notable_ascensions

> If NetHack is compiled for a 64-bit platform, the "long" type will not wrap around until it gets to 9,223,372,036,854,775,808. The above trick still works in principle, but will take a few hundred million years to complete.

Another laugh.