If you like point-and-click mystery games, this one is a pretty good one. You can interrogate subjects with multiple lines dialog that take different approaches, and a word above the char's head gives you a read on them. Make the wrong move, and they can turn contemptuous, cold, or hostile, and refuse to answer you. You have to play to each character's personality - if they are combative, maybe riling them up and encouraging a hostile response will make them shout the answer at you. If they are sobbing, compassion and tenderness will help them open up. A lot of mystery games just give you a cold list of questions and there's no nuance to it, so I really appreciated this.
The game is less about finding physical clues and piecing it together as it is trying to understand the people involved. Even though you know certain characters aren't the murderer, Poirot still works to unravel their relationship to the victim, why they respond the way they did, etc. The puzzle is about the people, not all footprints and snagged hidden threads. (I think this is a hallmark of Poirot novels themselves, but I haven't read any)
Finding clues, making observations, and solving puzzles was a tad bit tedious, though my frustration mostly came from trying to use the PS4 controls (see below).
Some of the mechanisms were incredibly repetitive, though. For example, everytime a letter from the killer arrives, you have to analyze the typewriter style with the letters before it - which involves clicking on the same 3 letters... every single time. And you have to do this at least three times. Each time you click, Poirot has a line, and you have to sit through it, so the process gets badly drawn out.
Also the characters all walk at a painful glacial pace.
But now let's talk about the PS4 version of this game. The controls are HORRIBLE. Where you would use a mouse, you use the right toggle stick to move a cursor around on screen. Which would be fine - but the curser starts out slow and then speeds up (you cannot turn this off), so it's very difficult to point to things with any sort of accuracy. Changing the sensitivity does not affect speed up time - it just makes the sensitivity ramp up SUPER FAST after a second.
There are dozens of 3D puzzles involving turning things, dragging items, clicking on small pieces and moving them. Sometimes the pieces you need to click on are so small (the hands of a clock where you could only click on the exact 3-pixel-wide line of the clock hand) that using the toggle stick to grab them is a frustrating nightmare.
There are some puzzles where clicking the wrong part of the puzzle prompts a line of dialog that you have to hit a button to clear, so every time you miss and click something 2 pixels to the left, you are given a repetitive line of dialog that pauses your game to speak at you. I wanted to murder Poirot about the 500th time he said "the little wooden flower is preventing the wheel from turning" tHANKS POIROT I HAD NO IDEA.
I'd definitely recommend this game for PC if it's your style, but dear GOD do not play the PS4 version.