So, I just binge-watched the first season on my DVR.
I love this show. It's very fun, well-written, with great characters and a really interesting time travel super-plot. Even the credit opening is one my favorites for any show.
The movie it's based on is a great sci-fi film, but I much prefer the series. Time travel is really hard to use well without writing yourself into all kinds of corners or contradicting the mechanics one episode to the next, but this show does quite well keeping things straight and you can see the effort behind the scenes to not just make shit up as they go along.
The writers obviously had all the main time-travel related events mapped out across at least the first season beforehand, so we didn't get the wasted opportunities of something like the Temporal Cold War of Enterprise. I like Enterprise quite a lot, but introducing something so universe-changing as a war across time and then doing essentially nothing productive with it before it was abandoned, was a huge letdown.
Production design for the future reminds me of the Fallout series, which is always a plus. The main actors are all great, with complex heroes and villains who alternate between being pro- and reactive, rather than one or the other being the sole drivers of the plot.
I'm not convinced that this series is aiming for a fixed timeline: i.e., even though things happen like Cassie getting killed and then resurrected, which on it's face implies a mutable timeline, it could be that the existence of a time machine only allows for cause and effect to switch sequence, but all causes and all effects that do happen, have always happened, and can only happen in the order and manner that they happen.
The bromance/love story effect on the outcome of the season finale, the reactions of the future baby cultists, as well as the villain's ardent belief in whatever prior knowledge they have of future history through the Witness, suggest that events were supposed to turn out one way, but took a different tack instead. And this seemingly without a temporal intervention changing the actions of Cole, Cassie or Ramse. As in, no one appeared and made Ramse give Cole the option of splintering Cassie, or made Cole stop and go back for Ramse.
Although, I suppose that all depends on what exactly the purpose of the hypnotic suggestion with the red forest that the villains gave to Cassie was supposed to accomplish. The writers could be playing a deeper game and Cassie's appearance, actions and influence on events during the climax could actually have been intended by the Witness all along, he lied to his cultists for whatever reason, and it just looked to us like free will changed fate.
Whatever the answer, I'm really looking forward to next season. Finally, an original Syfy channel show, with actual sci-fi, that's good! Now, as long as it doesn't turn out Cassie was a secret Cylon the whole time, we should be OK.