I saw a couple of videos of this game and it feels like the game is based, more or less, on a modified Silent Storm engine. Can anyone confirm this?

Not really?

The closest analogue to this game's "engine" would be the original Fallouts (1 and 2), as the UI emulates a LOT of it's functionality as well as look and feel. IMO they took that too far - the UIs of the original Fallouts were definitely NOT the best parts of those games.

Thankfully, they did incorporate several "modern" improvements to it, so it's much better to play than those games. It's even possible to give individual and exact orders to your team mates, as opposed to them being AI controlled (based on certain parameters you can set) - which they still do by default if you don't intervene. There is no cover mechanic as such (apart from walking behind an obstacle), there's no crouch, and the "stealth" is bare-bones at best.

That said, it's one of my favourite games of all time (since pretty much the day I bought it when it came out) - but the draw of this game is the plot, exploration and RPG mechanics. While the combat can certainly be challenging, it's neither the main focus nor the strongest part of the game.

This game was made with Unity
https://connect.unity.com/p/atom-rpg

Thanks for the info guys. Maybe it's the art style of characters and environment, with some UI elements (movement path indicators, character highlights, etc) that confused me and made me think that Silent Storm engine was involved.

I'm glad to hear that Atom RPG puts strong emphasis on story elements instead of combat, as the latter always becomes repetitive and boring eventually, because this type of games tend to overuse it. So any enhancements to it are always welcome, in my opinion. Even in the original Fallout series combat became quite a chore after a while into the story, unless your player character had enough skills to avoid it in some way.

I've put this game on my wishlist and will be buying it soon. From what I saw it looks very promising.

Big plus for the GNU/Linux version.

That's very true. But the reverse is also true, and that's what made me uninstall the game after 12 hours of playing: not enough meaningful fights, and much too much random talking, with too many unimportant characters who still have tiring complex dialogue-trees.
I love the game anyway. I wish it was more action oriented, though... I was exasperated by talking and wandering too long expecting a much needed bit of fighting. Only to be nastily overpowered every-time a random fight-encounter or scripted combat finally allowed me to draw my (weak-fragile-inefficient)-weapon.
There is a problem with balance there... But atmosphere is excellent.

I agree on the balance is a bit off. Basically I F5 when traveling the world. Though the Game is Very good.