Sachys: You can probably find a similar document online, but all you really need in the EU is a phrasing (like the one you have given in the OP - though one outlining your intentions as well) and the specific details of each of you (ie adress, website, tax numbers* etc) and maybe a few screens of the game (to bolster it). then sign, scan, send and have the other party do the same.
*presuming you're both declaring this - does help with the legalities though
blotunga: We are both just 2 persons, I don't think either of us has a tax number. The original is open source. However I think Google's problem are more related to trademark (I'm just guessing here).
F4LL0UT: I can't really help you with that but may I ask how Google requested this from you?
blotunga: Via an email exchange of course... I have sent them screenshots with my email exchange with the original dev, however they don't find that sufficient.
amund: As far as I understand this is not a ownership transfer and sounds similar to a CLA (Contributor License Agreement), you can read the one Google themselves use here
https://cla.developers.google.com/about/google-individual?csw=1 If I were you I would probably ask the original developer to write this agreement as he owns the copyright, don't know if it makes a difference but it could legally. This type of things need to be done with lawyers to be on the safe side, it could get messy if it's not clear. You might also want to read this
http://programmers.stackexchange.com/questions/58338/when-porting-code-must-i-follow-the-original-license blotunga: The original dev asked me to draft up one and then work on it together if it needs changes. We can't afford lawyers for this (I for certainly can't). It's not a commercial project on either sides, we're just two dudes who want to share stuff with the world. However it is harder and harder to do that.
Yes it's not easy to get this to work legally, I tried to write a CLA for my projects that allow others to contribute to the code but ended up changing the license instead that mention this type of things. In my license it says "You may reproduce and distribute copies of the Work or Derivative Works thereof in any medium, with or without modifications, and in Source or Object form", derivative work is that I would call porting a software/game to like smartphones.
