izigame.me

I wager this (along with Hitman 2 that I haven't played yet) is the closest to perfection this series is ever going to get. Basically every level is tons of fun to explore and is packed with all kinds of opportunities to get rid of your targets. The last game I really played in this series was Blood Money and this has upped the accident system of that game up to 11.
There are only a handful of maps but they each have a (large) list of challenges you can that persist between runs. The true fun factor lies in repeating maps to strive towards this challenge mastery until you know layouts and character routines by heart, to become the world class assassin the story wants you to be. It's wonderfully well done - though there are a few instances where some maps have mandatory non-kill objectives that become tedious on replays.
Plot-wise it's interesting but ends super abruptly, feels like I got thrown to the credits mid-sentence somewhere. If you're in it for the plot you almost definitely need to grab the entire trilogy I assume.