Hello flagyl, Since your question has already been answered over at our Steam Community Hub, I have pasted it here for you:

Signal Ops takes a very open ended approach to both gameplay and level design. We have build each mission with a goal in mind, and then made it so the player can achieve those goals in many different ways. We have also put in optional alternative goals and secret gameplay elements I don't want to spoil here. Although the game has a set narrative, we believe there is tons of replayability in the journey because of its design.

As to the length of the game, the first time we had to estimate this to someone we turned out to be way off the mark, in a good way though. We originally hoped players would take 6-8 hours to complete the game, but as it turns out we have become far too good at our own game in testing it, and people were reporting playtimes of 10+ hours! I think this might also be because we encourage experimentation in the gameplay so people are trying different approaches, plus it is quite challenging too.

Hope this answers your questions!