It would be nice to filter all sub 500mb games. Any chance GOG? Also, please be kind enough to include the download size on each games page. You generally do this on most but there are some omissions which is a minor annoyance as I am on a metered connection.

After you purchase your games you can tag them individually...

As for games to purchase... yes this does sound like a good idea. Though i'd have several tags,

TINY (under 100Mb, namely really old games and things like triple town).
Small (under 500Mb)
Medium (2Gb or less)
Full sized (4Gb).
Large (8Gb)

Then you have the larger ones.

XL (16Gb) - Note, every X is 16Gb
XXL (32Gb)
XXXL (48Gb)
XXXXL (64Gb)

etc etc...

For a collection of only four games, surely that can't be much of a problem...

I think it was obvious I was referring to non-purchased games.

No, it wasn't, and neither was obvious to the person that posted above my previous post...

Depends on which games you look at, I suppose. I found the opposite to be true: most game store pages don't list download size.

I don't know if they still monitor the following thread for feedback, but you can try adding your reply to New ways to browse and filter the game catalog for everyone.

Edit: relevant community wishlist entries
• https://www.gog.com/wishlist/site/sort_games_shelf_by_download_size
• https://www.gog.com/wishlist/site/search_by_size