If you still haven't played it, check out Riven which was recently released. It's a complete modern remake (plus some changes) of the sequel to Myst.
Leuthil
There are plenty of small indie studios that won't sell out, we just don't know who they are.
Palworld still ended up costing millions of dollars, although not tens of millions.
I think the dev pays for Imgur and other media hosting site APIs so that is also a factor. No other app displays media as integrated as Sync.
This goes way back to when Google first introduced IAP. They were pushing to remove dupes from the store because it caused separate reviews and ratings. It could be that they just temporarily enforced it and now it's not a concern for them anymore.
I remember when this happened to Sync for Reddit. Unfortunately Google Play Store, like most of these app stores, can enforce almost anything they want even if it's outside of their policy because some stuff is so vague. And it's usually hard to get clear information from anyone when your app gets pulled or whatever.
Are you mostly interested in the networking aspect? I'm not sure what Battle Bit does but many games employ a prioritization strategy when determining which characters should be updated per state snapshot for a client. Check out an old GDC talk about Halo networking, it's pretty interesting.
I think this is a written summary of the video: http://blog.wolfire.com/2011/03/GDC-Session-Summary-Halo-networking
This article is also informative: https://www.gafferongames.com/post/state_synchronization/
Braid Anniversary