It's 16-bit retro platforming goodness with Blink the Bulb! Take a little bit of Megaman, add a little bit of Sonic the Hedgehog then sprinkle in some holiday magic! You can find my thoughts on the game at 2:18:06 in the video above.
A lot of people (myself included) have noted that boss difficulty seems very staggered. According to Steam reviews, the day/night variety in stages affects the entire level, including boss mechanics.