[Android Apps and Games] MaR-V-iN:
Thanks for your feedback [MENTION=233416]emandt[/MENTION]. I appreciate it, although it's impossible for me to not agree with [MENTION=4004386]Ultramanoid[/MENTION] that it feels like trolling. I will try to answer to all your concerns.

It's true that Google API change. This project has some history and still uses some code from 2013. In the meantime, I saw some API changes, but most APIs stay stable. This is because not all play services users update directly and Google does not want important system features to break. I know that Google is aware of this project (or atleast some Google employees are) longer than you are and atleast one change in the web service implementation was targeting a third party software, with microG being the only one I know that fits into that. So yes, I agree that Google is unlikely to be happy with this project. But as Ingress players know, even the mighty Google is not able to block users out that really want to do something with their services. We will always find a way.

This project is all about privacy. As mentioned above it existed long before I posted it here on XDA and it was reviewed by several people. I also know that at least one "Android company" is working with it. The source code is still fairly simple to follow, and if you want you can check every future commit (and those from the past) one-by-one. It should also be noted that I built privacy related tools for Android the last years, some of them being published here on XDA as well or being integrated in e.g. OmniROM.

As I don't want users credentials to end up in wrong hands, microG GmsCore doesn't even safe or access your google account password, the login is done through Google's OAuth based website.

You complained that not "any warning/advice about privacy, credential or critical actions" was stated on the first post. As you mentioned that you're a XDA user for ten years, this can only be trolling: I never saw a ROM or Patched WhatsApp or darkened Play Store or anything else on XDA state something like this in the first post. And most of them were not open source. I expect users to be able to think theirself that, if you enter confidential data, random things might happen with that. I actually pointed that out by mentioning that "This is currently alpha-grade Software. Don't use it if you're not aware of possible consequences." in red letters :)

I agree that payments are crucial and it is important that they work fluidly. Until now I did not implement anything related to payments for that reason. Inside Play Store, payments are not directed through Play Services, so this is nothing to fear about (this is all about microG GmsCore now, not about a future implementation of the Play Store). On the other hand, as already pointed out by others, payments should be managed server side. It should NEVER be possible to pay more than needed.

Reducing the enormous size and bloat in Play Services is one of the goals of the project. And I'm quiet sure that this will be possible, because some things inside Play Services just don't need to be there or can be made a lot simpler. The majority of the size until now actually do not really belong to the project (but is the map rendering library used in the backend and the android-support libraries). I did not use proguard until now, I have a single release for all major instruction set (play services use multiple) and 500KB of assets that can also be reduced in size. Although i did not try it yet, I am quiet sure the size final packages size will stay below 10MB. I am not going into details why play services is so huge here, if you're interested in that, ask me when we meet in person.

And finally I wanted to point out that most Google applications do not user Play Services intensively. Play Store is using it primarily for Auth and checkin, as well as some smaller things like advertisement id. Only Google Plus related apps (Google+, Hangouts) use Play Services a lot. This is not really a surprise considering that Play Services was originally invented for Google+ and OAuth 2 APIs.

Finally, I'd like to thank you for the insights in your feelings about this project. I guess these answers will not sufficiently satisfy you, but there is not a lot more I can do. Trust me or don't - it's up to you.

Puh, what a post...