Questions about this game's DRM or lack thereof

[Deadlybot]

Do you have to use Steam? What makes you think that?
You just need to enter your serial, which is given where you login to shelf to download, to play the game. Once and for all. Frictional is really busy on making a really good game that they cannot bother with some sort of ubisoftish drm's.

What made me think that is the fact that some other games will make you use steam even for boxed versions, if the serial is all I need than I'm more than happy with that and as long as Frictional games keeps it that way I will keep buying their great games, thank you for the reply.