it would be time + 1 for every x sec of time = new variable it won't be able to be saved as a date/time variable in stead as a number. Just like a bonus timer in seconds.
So to set the variable it would be something like (d= +h= +m= +s= )= gamesaved
Thus gamesaved would look like
Updated: 03033600
and if they where to come back in 6 hours it would be
on load get value (d= +h= +m= +s= )= gameplay
Updated: 03063600
compare gamesaved with gameplay
for every x sec > then gamesaved = timeelapsed +1
set gameplay to gamesaved
if object is to move add timeelapsed to direction of move = new position of object.
Updated: The only issue I with the variable is that every day adds 76, every hour adds 40, minute adds 40. so you would need to adjust for that also.
I am pretty sure some one has created a .capx that does this exact feature you are looking for.