Really well made and feels great to play. Feels just like Ninja Gaiden and the artwork is very Castlevania. Backgrounds and sprites are fantastic and the levels are designed very well with difficulty and punishing enemy layout at the center of the design, which feels very NES appropriate!
Those guys who jump off the edge of buildings and hop around were so hard to avoid and then those skeletons seem to be hypercharged with the amount of bones they were throwing! This can feel a bit unfair at times, but again, it feels like a classic NES game where patience is required to beat it.
Music and sound effects are top-notch. Overall, this is one of the best entries I've played! Well done!