The ending to Lords of Shadow is full of mind exploding twists and fan-service

Here is a link to the ending and a discussion from gameinformer:   

I just finished the game, and that really took me for quite the turn.  
 

Post-credits scene redeemed the game for me. I thought all the chapters after the second lord were very mediocre, chapters IV-VIII is really where the game shines, in the gothic castles. But that end scene, holy shit. Slogra in the background, epic Dracula reveal, Zobek (how the hell is he alive and immortal?!), Satan (took me a while to wrap my head around that), it was awesome. I hope the second game makes some improvements to the basics (level design in spots was awful) and has a better story throughout the game, but I definitely want to see them run with this storyline.

To be honest it can actually be canon to the previous franchises if they choose to from this game's ending.  
 
Well for a start this can actually be a good anchor to explain why Dracula has been incredibly powerful and the main villain of the franchise making it canon to the other Castlevania titles except Lament of Innocence. Since they stated this is a reboot to the franchise this puts out Leon Belmont as the 1st wielder of the Vampire Killer, and instead puts Gabriel as the legendary vampire slayer that gave it's name and starts the Belmont line (without Marie Belmont though I don't know how). Though they will change what has been happening to Dracula if ever they will begin to follow this timeline as it will seem that Simon, Christopher, Trevor, and Richter Belmont is actually fighting and defeating their old ancestor and soon be again bested by Julius Belmont in 1999, then soon alongside Soma Cruz in the Dawn of Sorrow and Aria of Sorrow series.

I thought it was a fitting ending to the game. Quite the twist that I didn't see coming at all. 
 
And I was thinking that just because they show a modern setting doesn't mean that they cannot go back to a gothic style castle in a future game. But it would difficult to see a sequel to this game in a modern setting.

I was told beforehand that the ending was epic so i thought i wouldn't feel the same because i was expecting something to happen. I was wrong. 
 
I was completely satisfied after defeating the last boss. I totally wasn't expecting the Epilogue.   A modern day setting would work very well i think. It did for Darksiders. Although this game had a very lonely feel to it. Gabriel never really had any companions for too long and was on his own for most of the game, Which i liked about it,.