[TheToretto]

Yes it is correct, but pInfo[playerid][ZombiesKilled] value is both the first checkpoint's and the after checkpoint.
If you wan't to skip that, reset the variable

pawn Code:

zombieskilled = pInfo[playerid][ZombiesKilled];
pInfo[playerid][ZombiesKilled] = 0;

because basically on the if statement you got here:

pawn Code:

if(pInfo[playerid][ZombiesKilled] > zombieskilled)

If you kill just one zombie after the first checkpoint, it will be true.