We have large spreadsheets that when viewed in Office the top 2 panes and the 1st column are frozen so when scrolling you know what you're looking at. This excel document in Sheets To Go does not do that so it's basically unusable becuase you have no idea what you're looking at (or keep having to scroll way up or way over to see which column or row you're viewing).
This seems like a very basic feature of Excel not working.