I'll always be crushed that a traditional Sleeping Dogs 2 never happened.
I can't blame United Front if they didn't have the drive to make another huge single player game, but man Sleeping Dogs is my jam. I still think its combination of game systems have a greater cohesion and interlinked form factor, expressed in variances through the mission design, than anything in Grand Theft Auto and other much more popular sandbox games. Sleeping Dogs really hit a perfect sweet spot for what I want from these GTA-like games, and I feel United Front deserve an enormous amount of praise for realising what was a complex vision (given game system variety). Moreover, they chose a protagonist, supporting cast, and setting the likes of which we so rarely see in the medium. How many games are set entirely in Hong Kong? How many Western narratives have their cast voiced by Asian actors, appropriate for Asian characters?
It's just such a marvellous game that, for me, showed what can be accomplished in the modern-city cops-and-robbers sandbox game template when we're not circle jerking Rockstar. The latter has the budget and manpower to blow us away with asset detail and complexity, and an absurdly gorgeous engine, but Sleeping Dogs easily wins out for just all round better, more ambitious game design as far as I'm concerned.
The DLC was a lot of fun too, with United Front explicitly letting seriousness take a backset for mission arcs themed around supernatural and cheesy kungfu elements. Except for the last DLC, which was a legitimate epilogue.
So yeah. Really sad with how Sleeping Dogs will forever remain sequeless. It's still my gold standard for that specific style and genre of game.