Castlevania: Dawn of Sorrow is an action adventure developed and published by Konami for the Nintendo DS, in 2005. As we can read in Wikipedia, the production of Dawn of Sorrow was announced on January 6, 2005 as the first Castlevania game to be released on the Nintendo DS. The DS touch screen was a primary point of interest, and several functions, such as picking up items on the screen and moving them, were originally intended to be incorporated. However, scheduling problems forced the development team to abandon many of these ideas.
As noticed by argh4430, in the first two screenshots (the ones where Soma is fighting a manticore and skeleton archer in the Lost Village), those enemies are not there in the final version of the game. They are in the next area you visit, the Wizardry Lab).
Thanks to Xelba we have some more info about the beta differences in the early game. There was one screenshot that showed Soma fighting Gergoth at the beginning of the Lost Village stage. Also, an analysis of the game’s rom revealed some unused dialogue hinting about the piano room and Hammer wanting to help out Julius, Alucard and Yoko fight against Soma/Dracula.
While the piano room doesn’t do anything in the final version, there might have been a puzzle that rewarded you an item if done so correctly, but this is only speculation. As for Hammer, no action sprites were found other than his normal sprites. But the hidden unused dialogue between him and Julius as well as before the fight against Soma hints that Hammer was once planned to be playable in Julius mode only.