As another poster said Bugs happen. Beta testing for Bugs takes hundred of hours to find everything I remeber one floating glitch where ou had to jump and twist on a ceratin platform to activate its not easy you have to try 1000 of ways to do something as simiple as open a door to figure out does it have a glitch in it.
The testers think they have everything but there is always something and the more complex something is the more likely a glitch is to occur. I have yet to see a game released 100% glitch free.
Also take this in to mind testers usually number 10 or so I think the biggest I ever heard about was 100 for a company team not a public beta testing. When released into Public a Game goes into several 1000 hands easily and that is 10 times more then the testers and 10 times more likely to find a glitch that was missed.
Many of the issues players find will be patched and fixed because now someone is aware of them when before they didnt even know it exisited.
This game has an exceptional amount
Not really I have seen I think 4 of them? Angel glide glitch, Hunter not doing anything, One more that I dont remeber and one I ran into the explanation Guide not going away it went away after a cutscene but not before that.
Mass effect 3 had a ton of glitches same with MGS4 and several others I wouldnt say this is alot of glitches in comparsion but I would say a medium amount because there is more then what I know of I am sure. It takes time to find and fix glitches the game has only been out 3 days offically. --- I have an answer to everything whether its a good answer is entirely irrelevant