From what I've read about it, from reviews on Jalopnik and Rock, Paper, Shotgun, this isn't just a new MudRunner with different terrain. Instead they have added a lot of gameplay elements with missions, goals and reasons to move stuff from A to B besides making money. Here's what Jalopnik had to say in their verdict:
I put in some hours on MudRunner, but burned out since there wasn't a lot of gaming in the simulating. However, SnowRunner seems like something I could put some time into, like American Truck Simulator. I'll probably be picking it up.SnowRunner is simultaneously casual and hardcore. It’s a nuanced and intricate execution of: “Here’s a sandbox, go push some trucks through it” that’s satisfying to play for anyone who’s intrigued by problem-solving and cool trucks. But it also moves slowly and quietly enough that you can successfully play while you’re on the phone with a friend, stuffing your face with chips, sitting through a 10-party conference call, or not totally totally sober. Or some combination of all the above.
As a simulator, it’s a decent primer on how different functions and accessories help trucks get through various terrain elements. As a driving game, it keeps finding carrots to dangle in front of you to pull you in for another hour of play. SnowRunner is constantly encouraging you to press on through mud and snow to unlock more powerful vehicles, fix the towns, and find out what’s over the next ridge.
I can’t wait until work is over so I can play it again.