All the reviews here are true. Two (decent and fun games) in one? You can't go wrong with that!!!

User Rating: 9 | Castlevania Double Pack GBA
So they decided to combine HoD and AoS into one pack. And this game is worth the buy and the play. This is the second Castlevania game I'd played. And this is good. So here's my review on each game:

HoD:
+ the 2d-platforming gameplay
+ nice spooky GBA graphics
+ the 3-5 hours time spent on it...plus some replays
+ nice map layout

- too short of a game
- needs some heavy plot aside from battling the Count himself..

AoS:
+ improve graphics and gameplay
+ nice animation( especially Soma's and Julius' animations)
+ the soul system and being able to equip weapons other than
whips
+ the good replay value
+ always the nice map layout
+ and the 3-5 hours time spent on it....plus replays

- why is it always too short?
- plot's script needs imrovement...

All in all, it's a great bargain. 2 brilliant games in 1.
They should've include CotM and made it into a 3-in-1 game, what do you think? :)