missing error... there are two of those, 1 is in act 1 and it just let you die falling under the map, but there is a code written under... the second one is in act 3, it teleport you in the "city" in the other side of the invisible walls, you can explore or hunting the 7 achievements related to go to places like hospital or supermarket...

another thing, if you stay 10 minutes without moving at the very start of the game, so start and do nothing for 10 minutes... a green cube will appear on the street, you need to open the console commands (with an english keyboard) and... ... there is a secret glitch world that you need a video walkthrough to complete because you need to type codes that you can't guess, you need to know them, and it's literally impossible without a guide...

those are some of the wierd or cool stuff, the biggest things...

Wow that's cool