I had Farm Heroes Saga, and the update didn't fully install. The icon was greyed out, and like everyone else I also couldn't delete it. None of the other methods here worked for me.
I have just found a solution which worked for me, and I'm pretty sure it will work for anyone else. I hope I'm allowed to mention a 3rd party app here as this is an issue which needs addressing, and all official Apple solutions has so far failed.
OK, all I did was download an application on my Windows PC called "iFunbox". It is also available for the Mac (naturally). It's an alternative to the iTunes software.
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Once installed, I plugged in my iPad to my PC, then I ran iFunbox.
I then clicked on "Managing App Data", then underneath "All My Apps", Clicked on the offending Farm Heroes app and then clicked Uninstall. Hey presto, it was then removed from my iPad. I was then able to redownload and install it. Because the game is connected to my Facebook account I didn't lose any progress. If you do lose any progress on a game you were playing, well at least your iPad is fixed.
Hope this helps.
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