Almost all of them.
Vs. Super Mairo Bros. has many more difficult jumps and less 1-up Lives. The PC10 is identical to the NES version.
Vs. Castlevania seems to be a little more difficult as far as taking more damage from enemies and a lower time limit to complete each level.
Vs. Duck Hunt has the ability to shoot the dog and has bonus levels of shooting ducks.
This is just a few examples. All of the PC-10 games are identical to the home NES counterparts. The Vs. are all slightly modified to either be more difficult or to have some sort of bonus level (Vs. Excitebike has a jumping contest as a bonus level for example)
One that doesnt fit the mold is Vs. Top Gun. I believe it is just like the NES version, but i havent checked it out enough to say definitively.