I did not complete the whole story (no specifics b/c of spoilers: so far I spoke with somebody in cyberspace, uploaded something on some base and spoke to the guy from the transport) so not sure it is going to be the whole game but I get the impression that the timelimits in the game are similar to the original Mass Effect: colony Ferros is under attack, you land there kill few geth in the docks, see colonists trying to hold against one geth, you say "Eh, they'll do good without me...", take off from the planet, go through numerous uncharted planets and quests, save Liara, have a chat with Rachni Queen on Noveria and chat with Sovereign on Virmire, then come back to Ferros to find same colonists fighting same geth. So basically if you need to complete 3 missions during the sunset go onto the one that sounds appealing to you on the 1st sunset, complete the mission, go to the 2nd mission location, in a true Witcher spirit click on the "Skip time" (they really needed to put it as "Meditate" :P ) till sunset, complete it, then same with 3rd one.