My in-game options were set to 1920x1080 during that play through although trying to play it again ends with with a little too much lag.

My resolution is 1920x1080 while in-game

6 minutes was just a guess haha but the first wave did hit me (the ones in the prison) and this happened once I 'won' that wave.

I don't use debug commands and I use the steam version. The game is how I got it from steam, no meddling.