I was in BLR in 2012. Newish airport that requires a same day boarding pass to get into the building. Once inside the airline ticket counters may not open until a couple of hours before their next flight departs. I got there early and had to wait for Air France to open. Not much other than a coffee/tea/snack place in the departure hall prior to security. The tea was pretty good.
There was a smoking booth just prior to security after taking an escalator up a level.
Security insisted that each piece of carry on luggage have a paper tag so that they could stamp a "checked" indication on it. My plastic airline tags weren't acceptable.
The Air France lounge was OK. I didn't really go or do anything else in the airport.