Tried out the demo.
Going to list some things I noticed while playing the demo.
-Mapping is a bit bland, but not too bad.
-The music playing in the castle after the intro is a bit loud compared to the sound from the intro.
-The choice to look for the item in the pile of stones was unnecessary.
-The character's comment on finding the sword in the chest felt a little... random.
-Making the character step forward after using a save point is a little annoying (since it's slow) and unnecessary. Also, it would be nice if the save point was only activated by interacting with it while standing on it, not just stepping on it.
-In the room with the vine going down a gap it puts me in a room much further away than the staircase takes me downstairs, while it's right next to the staircase before climbing it.
-A door I entered from below, and end up entering a room from the right.
After playing some more for a while I gave up on it.
-It's same big room after same big corridor after same big room after same big corridor, with little to no direction on where I really should be going.
-After 30 minutes of playing I still don't know WTF I am trying to achieve in this game besides finding keys and walking through the same big rooms and corridors over again. Neither do I know where I am (besides being in a dimension rip), what this place is supposed to be, who the guy in the beginning was, who my character really is, etc etc.
The game seriously lacks in the direction department. I want to know what I am doing, where I am supposed to go, why I am doing this etc. Don't give me "basic keys" and expect me to walk around your 1000km2 dimension rip for no apparent reason hoping I'll find the right doors to unlock.
I want to find out more about my character, the other character I met with, and the place I am in within the first 30 minutes of gameplay besides the intro cutscene. Give me some meaningful mono/dialogue during the search for stuff in the castle.
I don't want to look at the single same big rooms and big corridors for so long. Make the castle smaller, cut it up into seperate sections if you have tileset limits, and make each section of the castle different. Not only would it make it more interesting to go through, it would also make it easier to recognise certain sections, and easier to navigate through.
Make the place represent more of an actual place. Right now it's just random rooms and corridors with the same paintings and holes and statues everywhere. Make stuff like towers, dungeon rooms, barracks, a throne room etc.
Battle system is basic, but it works. I think you were a little too generous with potions and other items, especially considering saving points heal back my HP. It would be nice to have bats drop anti-blind instead of antidotes, because then I could actually put my loot to use.
Levelling up seemed to take a lot of battles, and after some levels I still hadn't unlocked a single special skill. Something to look into?
On a more positive note, I don't think I saw any typos, neither were there any mapping errors or other bugs, so that part you did get right.
Conclusion: You were off at an OK start with the intro and the beginning of the castle, but the boredom quickly strikes by leaving me in the same big place without giving any directions or additional story elements whatsoever. Needs a lot of work cutting down on repetition and adding stuff to make it more interesting.