I have waited with my review for the Lords of Shadow DLC simply because both packages are essentially one story. So my review here will affect both DLC packages since you need Reverie to play Resurrection. Hence the question: Is it worth it?
Short answer: No.
Long answer: Reverie, which is neatly priced at 7.99 bucks is by far the better package. It has more stages, is longer, features more of the classic Castlevania in it, has better music, more battles and is less frustrating. Resurrection, the sequel DLC was supposed to be longer with more action and better gameplay. However, that was not the case. The title is frustratingly hard and only features two rather short stages. The Battles were challengeing and all, and I was okay with them. But there are only four! battles, two of them which are essentially the same boss fight (bringing it down to three battles).
Whats worse, the climbing sequences and platforming elements have a frustrating design, with hurr up or instand death pressure written all over them. When I was shelling out the ten bucks for Resurrection, I expected an hour long quest to defeat the very evil others have died to imprison and see Gabriels descencion into what he will eventually become. However, all I got was a hide and seek game with the punishment for being found is instant death.
Mercury Steam had the opportunity here to craft an extrodenary tale of darkness and destiny but they failed on almost every level. The story does not make any sense, promises that were made have been broken and the final pricetag of 18 bucks for roughly one hour of gameplay is just too expensive. If you liked the main game, get the DLC once it is cheaper. If you can snag both packs for a total of 10 bucks go for it, if not, leave it be.