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?
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.