I feel like Koudelka is one of those games that sort of becomes a bit hard to appreciate without actually taking into account the context in which they were released: on a technical level, it was universally acclaimed for being highly innovative in its use of motion capture and for the creation of truly stunning cgi scenes, elements that for his time certainly led the way for new perspectives on the expressiveness of storytelling through the physicality of characters.
It is also certainly interesting how these technical factors have been applied to a gothic horror setting, created with the goal of providing an experience that is dense with atmosphere and rich in interactive cues, with many environmental puzzles and objects to collect to enhance the gameplay experience.
Unfortunately, Koudelka was also, and above all, a title with a troubled gestation, which had to juggle too many different angles without really coming to a sufficiently defined direction, ending up integrating very different influences with, in my opinion, very variable results.
It was definitely an overly ambitious project for a rookie independent studio, which had to manage an overly complex balance between survival horror, tactical rpg-like elements and genuinely wanting to push the immersiveness front.
What we are ultimately faced with while playing Koudelka is a not always satisfying experience, one that works quite well as an rpg and much less so as a horror game, with great charm and a real passion oozing from every angle, very fascinating to look at but not as original to play.

I think AC2 is a good entry after deciding to embark for this series. The usual campaign is 21 missions, each could take from literally a couple of minutes or 15-16 on the higher end depending on how good you are and whether you clear the map or just focus on the main objective. The campaign has a divergent path halfway through to encourage replays.
There's quite a few aircraft available but unlocking them is easy and most are straightforward upgrades rather being distinct fighters with quirks so usually you only decide between 2 prime planes depending on the mission.
The combat arcadey with enough difficulty that expectedly ramp up, I recommend learning the expert control layout because it gives you more control and a wider range of play, while the other exhausts combat quickly way before the campaign's over.
The soundtrack has some strong standouts, I never thought I'd be firing air to air missiles to a jazzy track. That was great.
Sequel is supposed to be the one starting the ace shenanigans so here we go.