GhostMatter: I can still access my previous purchases but for how long?
As long as they keep to that promise, I don't see any real problem.
And if the games they had sold to you were DRM-free (I presume they aren't?), then I could even understand if at some point they run the whole service down, at least giving a long time for customers to reclaim their purchases for local repository. After all, realistically G.G.com will not be around forever either, but as long as you have downloaded all your purchased games before the final shutdown, you should be fine.
If, however, you find at some point that you can't install nor play your purchased games any more, due to the changes or shutdown of the service (not related to your own (lack of) actions), then you should be very angry.
I think this case also shows how easily a digital store, who starts selling "also" Steam keys, easily slips into a shop which delivers only keys to other major services (like Steam), and shuts down its own infrastructure and service, not competing with the other services anymore. This is just a reminder to the folks who say G.G.com should start also supplying and selling Steam keys.
tritone: If not, and say I wanted to use Impulse to re-install a game... could I just copy it to the "Archive File Location" folder and use Impulse to install it? I'm afraid at some point in the future, even though I bought and downloaded the games... they aren't self-installing like GOG purchases, and I might lose the ability to install them, say years from now.
Bingo.
People don't mind DRM... until it bites them to the ass.