crash: extremely serious and prevents the player from progressing in the game. can also freeze the game or kick the player out completely and display an error message.
critical: major functionality problem but does not prevent the player from progressing in the game. examples are a level missing a lot of textures or a major gameplay feature not functioning as designed.
minor: noticeable by the player but does not detract from the overall game experience. stretched textures and typos are minor bugs.
this last glitch with walking through the walls i would call a minor bug. also, as that is not the "normal" path to take to get to the next area i would think that not many people would find themselves walking through the same walls as shown in the video.
bug descriptions paraphrased from "the game production handbook" second edition by heather chandler. it's required for one of my game development classes this semester which is why i have it.
there are generally three types of bugs concerning video game development. crash bug, critical bug, and minor bug. and due to time frames given to development companies by the publisher who is paying them for the game, the developers have to do the best that they can with their limited time. developers are constantly pushed to deliver the game, even if it contains minor bugs.