GOG.com is facing questions from the gaming community over a recent rejection. Zach Barth, founder of Zachtronics, is the creator and developer of Opus Magnum, a machine-building puzzle game that came out just last month. This is his sixth major commercial release, and all five of his previous titles have been released on GOG.com.

Barth took to Twitter to give fans some news about his latest title. Apparently, Opus Magnum was rejected by GOG.com and they were unwilling to publicly release their reasons.

I’ve had a bunch of people ask me if Opus Magnum will ever be available on GOG. Here is the response I got from them when I asked for a reason I could share publicly for why they didn’t want to carry it. We would still like to be on GOG if they change their mind! pic.twitter.com/Nwb7JzLVI1

— Zachtronics (@zachtronics) January 5, 2018

Their statement doesn’t answer many questions about why the game may have been rejected, but it seems that Barth was suspicious that this might happen. Just after Opus Magnum came out he tweeted about the possibility that GOG.com might not allow the game and speculated on why that might be.

Part of the appeal of GOG.com for some players is that they curate their content. Platforms like Steam which do little to no proactive curation often come under fire for the quality of games that they allow on their service. But Opus Magnum’s rejection is puzzling for many players.

The developer is experienced, the game is polished and well made, and it has received overwhelmingly positive reviews from critics. It is understandable that GOG.com wouldn’t want to release their exact standards. They would be more open to criticism from anyone who disagreed with their methods and would receive more submissions just trying to squeak by the stated benchmarks. But players are having trouble just accepting them at their word.

Discussions have appeared on Reddit and other forums about the pros and cons of curation. Some feel that Steam is far too liberal with what they allow to be sold on their platform and prefer that GOG.com stick to their curation to keep the quality on the platform up. Others argue that if strict curation will keep good games off the market then something is wrong with their system.

It looks like GOG.com won’t be revealing their reasons any time soon, so the community will just have to speculate. The discussion this has sparked will likely continue as the digital marketplace changes and platforms continue to compete for market share. For now, you can check out Opus Magnum on Steam.