If you're planning on looping this the length seems adequate and it wouldn't be too annoying. However there are a couple of problems:
-Snare drum in sync with the piano sounds terrible.
-Add some variation in the beat of the snare drum at the end as well
-Piano part towards the end gets a bit out of hand, it sounds like you are hitting random keys with no particular beat or tempo.
On a positive note I like the overall tone it sets, sounds very Castlevania dungeon-like.