help with combining data from 2 sheets

I am playing an online game, and a bunch of us are working on a map of the game.

I made the original map and sent it to the players then they update it and send it back... now my problem is combining the maps we have into one

they are all the same format same area.

we used just simple letters and colors

i thought i could just copy and paste the area to update but every time i try it says that excel has a problem and closes and this is only a 20 by 20 area

since the map is 600 by 600 this would take forever doing it in smaller chunks.

any ideas
thanks in advance
unclegar95

You cant open a spreadsheet with more that 256 columns in excel.