I've seen the decompiled source code for Wizardry 1 and 3, and the code for 1 is a mess in parts (see, for example, the HAMAN/MAHAMAN routine).

Ultima 1, in its original version, was written in BASIC. This, of course, affects how things like numbers were represented. (The later remake, as well as Ultima 2, were written in assembly language.)

In Ultima 2 and some versions of Ultima 3, if a stat goes above 99, or certain other values (like gold, maybe food and, in 2, HP) go over 9999, the value will actually roll over. For example, if, in U3, each character is carrying 2600 gold, and you have somebody pool the party's gold, that character now only has 400 gold, with the other 10,000 just vanishing. (Apparently, the IBM PC version of Ultima 3 has checks to prevent this sort of overflow; I heard that pooling gold in this situation won't be allowed. Because of this, and the fact that the IBM PC version lets you transfer over 99 food/gold between party members, I think that may be the best computer version, even with the lack of music, the treasure chest bug, and the scarce overworld encounters; it helps that this version has a nice mod out there that improves it.)