Unbelievable fast battery discharge on some games
Your answer lies in your question itself, you have mentioned that other than games the phone runs normally! I think its the games that are causing this, anyway to make sure of that please read ahead.

Can you specify if it is one particular game or all games? If it is just the games mentioned in the other link you have provided, can you just try with the following games and let me know how it goes?


Temple Run 2 
Subway Surfer


The games you have mentioned Paradise Island and Dragon City are really heavy games!

Also do you play with the charger connected or disconnected? This was unclear from your question.