The Messenger. Pretty good Ninja Gaiden homage. You control a ninja fighting the usual demons trying to erase humanity. This is done in one of those retro "8-bit" styles. After a while the game shifts to the future, and everything evolves into a 16-bit style, and then it introduces the concept of moving back and forth in time and starts allowing you to freely explore the map you've been covering through the game so far, becoming more of a Metroid-like game.
The game can be tough in spots but it's generous with checkpoints, it controls pretty well, and a fairly gentle difficulty curve (when I started playing, I was worried that it was way too easy). By the time you finish, you'll be pulling off complex maneuvers involving double-jumps, gliding, grappling hooks, and attacking in between every other move.
The graphics are fine. Like a lot of these retro-games, the graphics aren't really convincing compared to what was seen on actual 8/16-bit systems, but the art is pretty regardless of which style is used and idea of switching between graphical styles to connote time-shifting is kind of clever.