The bundle is inflated in price due to Lead and Gold which imho is not worth it. That game alone is multi and has been dead mostly on servers for eons. Krater is supposed to be good but i havent played it for a while. Its co op rather than multi i think
Krater is an odd beast, really, and I wonder what they were thinking when they made it. It is filled with Swedish (and sometimes Swedish pen & paper RPG) in-jokes, which might turn out to be very hard for most non-swedes to actually understand.
Gameplay is so-so, but the setting is nice and charming. I can't wholeheartedly recommend it to someone not from Sweden or who is not at least very familiar with Sweden, but at that price, it might still be worth a look.
And the game has a full-length singleplayer campaign. I have not even touched the co-op yet, so I can't comment on it.
Krater reminds me of many of the RPG's from the early/mid 90's here on GOG. It's very unique, and it has high ambitions. But it's a mish-mash of ideas that don't really go together correctly like someone duct taped it all together. At times it feels like the various bits and pieces are at odds with each other. It's an open-world type game with a strict level cap structure. You're supposed to change party members frequently but you can individually upgrade them as you go along so you get attached.
Even if they didn't achieve their goals, you have to admire their ambition to try to make something really unique in this day and age.