Generally speaking all DOS versions were downward compatible, so if an app worked on DOS 4 then it should also work on DOS 5. However, programming can be as idiotic as the people practicing it, so if some programmer instructs his app to grab the number behind the period of "MS DOS 3.3" it would obviously crash on MS-DOS 4.0 or return simply nothing. "Most" games work on all DOS versions, generally speaking the higher DOS versions support more games than old one. There are also technical reasons why you may have less fun with an old DOS, for example keep in mind that MS-DOS 3.2 supports 3.5 inch floppy disks, but earlier versions will not, so that would definitely suck if you have a machine with a 3.5" floppy running MS-DOS 2.1. Other restrictions refer to the graphics, usable amount of RAM and maximum size of a HDD, so this may really matter to you.

Because 1985 can't recommend MS-DOS 6.2 because it's before 1994. Mobygames' tech info is intended to be taken right off the boxes themselves. It is an authorative historical database, NOT an "can i run it" joke site where kids will recommend 'uh i think u must use dosbox 0.63 get it from abandonware site here'

Good point - thanks!