Well, there is no such specific M.Tech. (in Game Programming) course offered by any Institute in India. Some institute offers Diploma in Game Design, like AIGA, Bangalore. One another way is after completion of B.Tech., you can look for a job of Game Developer in companies like Jump Games, Gameloft Software, LiveWire Telecom, TigerTail Studios, Spiel Studios, Carbonon Tech Software, Vimukti Technologies, Aten India Software Solutions ..... If you get a job then you will become more familiar with real time Game development rather than just pursuing a course.