The Messenger is a self-described love letter to 8-bit and 16-bit platformers and action games, and it just so happens to star a young ninja fighting to defend his clan from demons.
As you may have guessed, The Messenger was heavily inspired by the old Ninja Gaiden games—so much so that, speaking with Polygon, lead designer Thierry Boulanger said much of his development history can be traced back to Ninja Gaiden 2 on the NES.
Boulanger and developer Sabotage boast of "challenging gameplay and tight controls" on Steam, but The Messenger's most interesting tidbit is its generation-hopping aesthetic. When I said it's a love letter to both 8-bit and 16-bit games, I wasn't kidding: partway through, the whole game upgrades from an 8-bit action game to a 16-bit Metroidvania game with improved music and visuals. You can also swap between the two styles mid-level to solve puzzles.
The Messenger was designed to be speedrun-friendly. Boulanger says there are multiple paths to each level: the normal, obvious path, and then paths with huge shortcuts hidden behind skill-based techniques like the "cloud-step," a situational double jump which can only be used when you hit something (like an enemy or an enemy projectile) mid-air but can also be chained infinitely.
The Messenger looks like one to keep an eye on as it cloud-steps toward its 2018 release.