Thanks Hope you like the way Balls Breaker HD is done
1) Currently I am using Cocos v3.12. I am going to switch to the latest version after iOS release.
2) Yeah, it was quite difficult to make the game "smooth" on Windows Phone. Here are the main things I have done.
First of all WP is not good at multiple GL calls. It is very important to minimize GL calls. To do that I am using spritesheets. I also grouped my sprite textures. For example in the main menu I am using only one texture/spritesheet for all my sprites.
The second thing is to use bitmap fonts (for dynamic and static texts). Yes, it is time consuming to create such fonts but the performance boost is very high (less GL calls). If, for some reason, you have to use TTF fonts then don't use any "effects", like glow/bold etc. I noticed that on WP it slows down rendering a lot (for example my Help dialog was a fps killer :P). Currently Balls Breaker HD supports 10 languages with bitmap fonts - so it is doable
I hope I won't be killed by someone from cocos, but.. don't use UserDefault for storing game data. In Balls Breaker HD I am keeping quite a lot of player data and I noticed a lot of glitches when I was reading/saving values with UserDefault. I discovered, that every time you read/write some value it reads/writes all your database file. So for example if you need to write 10 values it will physically write the file 10 times. Fortunately it was quite easy to write "custom" version of the UserDefault with load/save approach. Maybe there is other way to do it, but I couldn't find it
The biggest advantage of running the game on WP is that on Android and iOS it works pretty well
3) I am using "pure" cocos2dx. I have custom level editor. All the game is coded with the cocos2dx animation system. No scene editor
Feel free to ask if you want to know more
All the best.