I'd be so curious to see some sales numbers, not that it would ever happen. For example how many more Descent keys, at 75% discount, were sold compared to Descent 2 or 3, at only 66%.

Or how many more Prince of Persia keys, at 75% discount, were sold compared to Prince of Persia 2, 3 or 2008, which were only 66%.

You are too curious. No one official will ever say "sales numbers".
You may check discount values compared to previous, and decide for yourself "to buy or not to buy" :
Descent - 75% - highest ever*
Darksiders II: Deathinitive Edition -85% - highest ever*
Prince of Persia: The Sands of Time - 75% - highest ever*
GoNNER - 80% - highest ever*
Homeworld Remastered Collection - 85% - highest ever*

Was it worth it? - It was Gog's decision to set up such discounts...

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* highest ever - since the start of www.gogdb.org database

I know, that's exactly why I said I'd be curious to see some sale numbers, even something as vague as "sold twice as many". As far as "to buy or not to buy", there's no contest that everybody that could afford it, should get them at the current discounts. I already got them all, many a long, long time ago.

Thanks for keeping it updated while I was away.

More like the publisher's decision, GOG can present their sale format and at most ask.
As for sales numbers, sure wish I'd see those, just for the sake of curiosity and statistics. But saw even devs saying they're specifically banned from saying anything, even comparisons like the "something vague" mentioned. Which is messed up.

By the way: the discounts are always "round", i.e. -40%, -45%, -50% and showed in "game page header": the page itself shows discount in "current currency" (in $ / EUR / RUR / ?) but the page is always named "in abstract round discount"

for example:
Star Trek: Judgment Rites -49% 4.39EUR $4.99 2018-09-06 10:00UTC
...
[REPEAT] Star Trek: Starfleet Academy -49% 4.39EUR $4.99 2018-09-06 13:00UTC

on these games discounts may differ if the price is in $ or in EUR, but "official" discount is 50% (not 49%)

You could look at the Popular tab on the front page to get an idea. Those lists seem to be based only on very recent sales. The top of the list is usually those titles on sale in the past week.

I see:
#81: Prince of Persia: The Sands of Time
#99: Prince of Persia
#116: Prince of Persia: Warrior Within
#128: Prince of Persia: The Two Thrones

So in this case, the Flash Deal is winning.
#134: Descent
#145: Descent 3 + Mercenary
#153: Descent 2
#290: Descent: Freespace Battle Pack

In both cases the Flash Deals are "winning". Not sure if it is based on number of units sold or dollars spent, but if the latter, it's even more impressive.

I always doubted that the lists were updated for recent sales, but now that you pointed it out, and having checked it out personally, I'm convinced.

I would assume to be based on the dollars spent. ELEX, isn't a game with enough hype to move too many numbers from new gamers. But there are fans of the old Piranha Bytes games, who would surely buy it on sale, even though I'd expect some might wait for an even deeper discount. So it being number 2 on the list, could only be achieved if the list is based on money raised.

Or, it could be because it has its highest historical discount on GOG yet, thus it is selling like hotcakes.

Of course it's selling like crazy due to the discount. But who is buying it? The old players, who recognize the developers, or new players who saw the game on a let's play/stream. I assumed it's the old players, so the overall money raised would allow it to hit a higher place on the list, than the number of keys sold would. It's all speculation.

I wonder if they would put 75% off discount for other Prince of Persia games for Anniversary Sale. Or maybe a bundle with that discount.

About ELEX, I have seen at least 2 recent reviews from this sale, and while i actually can't find any of the reviews (what this means? refunded or deleted?) both were from fans from Gothic. Not very good reviews, also, but the thing is that probably a lot of players from previous games that were not convinced this time are now buying with the new highest discount and just some new players tempted even with the mixed reviews that the game has.

Anyway, i also assume the popular tab is updated from time to time and reflects more or less what is happening during the sale. I would say that only the first and probably the second page is being updated, grossly, because from the 20th game on, little changes and there are games constanly in those positions with or without flash sales. I don't know.

It's worthy to note that a lot of flash sales are not reflected on this popular list, and maybe that's something for GOG to consider when offering this flash deals. There are games deep down in the popular list and remain there even after 2 or 3 flash deals.

Finally, i agree with others (here and on the main sale thread) in that a historic best deal is not, per se, worthy of a flash deal, specially when it's happening the same on other stores in this very moment, and it's not anything exclusive of GOG store (Frostpunk, for example)

Looks like they are making a reset in 1 hour with new flash deals?

Oh my, you are right.

Well, this atones somewhat for the sin of boredom which the last two days of the sale committed.

It doesn't completely absolve them, but it helps.

Crap, I missed getting Battle Chasers because I was undecided on it. Oh well.