First off, I haven't played the first game. Thus I receive the privilege of having an unbiased opinion about the series, but I might lose some context about what I am playing.
Interesting take on the whole fixed side-scroller beat 'em up. Good pixel art with fantastic animations. However, the gameplay here is pretty stale. All that you're really doing is stabbing things to get lifeless shards so that you can by powers to get more lifeless shards, to get more powers...and so on. There's nothing that is really keeping me playing, nothing compelling about the game. I found myself bored in under 5 minutes after finishing the tutorial. The medals will add a little to this, but not much...a game should be good without achievements. It might help if I had some sort of back story to go with, or i knew the reasons specifically why it mattered that the mortals were trying to achieve immortality (this could possibly be a link to the last game that I have missed because I haven't played it, but even then a recap might be nice), but right now the light humor of "Challenge accepted!" doesn't quite cut it was a reason to play.
Still. Fantastic art.