For those confused, Hot Potato started off as a gamemode for JRMP that I made years ago. After that I decided to remake it now that I know what worked and what didn't in the old version.
The version you have here (in my opinion) isn't as playable as the current 1.7 release. Some notable differences:
Final countdown is less epic
UI isn't as polished
The stun mechanic instead turned people into ragdolls, which was inconsistent and you could be stunned multiple times in a row by falling due to no fault of your own.
However if for whatever reason you want a less polished 1.4 version, this is it. Just replace some JRMP sounds for vanilla counterparts.
For most people though, I suggest getting the more polished 1.7 version.