Yes, locals have confirmed that it could get as cold as -50c here during winter but only for a maximum period of 1 week. The same way that in Manila we expect typhoons to come and go during the wet season. It's not constantly -50c as i first thought it would be. The average winter temp is around -15c to -20c, which is manageable if you have proper winter clothing.
Speaking of clothing, we really made a good call on the down jackets from Northface. It was a bit pricey but it does keep us warm and healthy. P and I both have a tri-climate jacket and a down jacket from Northface that we mix and match depending on the temperature. On cold days with snow or strong winds, i attach my down jacket to the waterproof shell. On very cold days, i wear the fleece lining from the tri-climate jacket with my down jacket and just a regular sweater as inner wear. I also wear leggings underneath my pants for extra warmth.
Shoes with good insulation and proper traction are a must-have. I brought one very dependable all-terrain hiking shoes that is water repellant which i use most of the time because it's warm and keeps me from slipping on the icy sidewalks. On days when it's snowing and the sidewalks are covered with a layer of fresh snow, i can wear my leather boots with heels because it's not as slippery. Note to reader, boots must have lining to keep your feet warm.
Aside from a warm jacket and proper shoes, it is also important to have a thick warm bonnet and gloves for good insulation. I think the best place to buy warm bonnets and gloves would be here. I just purchased a new bonnet last weekend and it did feel a lot warmer than the one i used to wear. Siberians never go outside without a hat. You can leave home without your gloves but never leave home without your bonnet.
The best advice i got from locals is to stay indoors when it gets really cold. The heating in Novosibirsk is centralized and so all the buildings are well-heated.
Contrary to what i initially imagined, Novosibirsk is nothing at all like that scene from Tomb Raider. It is a proper city with well-developed infrastructure and highly-educated citizens.