You had a terrible nightmare. You were in a castle and there was horrible things. You decide to go find out, what is wrong with this castle. [Requires Justine!]
Mapping: The thing that I think suffers most in the mod is your sense of lighting. There are multiple levels, if not all which lack a boxlight. This will cause many things to difficult to see, and makes the lantern a MUST in these cases which is not a good idea if it's such the case for all maps.
Overall indoor mapping is okay in my opinion with a few tweaks needed here, and there as well as addition of more detail. Also be sure to mess with tile values so they don't get repetitive.
Outdoors mapping was quite lackluster as there was very little detail throughout the whole thing. Add vegetation, rocks, or the sort to liven it all up a bit.
Story: The premise of your CS I feel like could've been expanded upon to make for something interesting if you decided to flesh it out, and make a believable environment. However, in your CS we are treated to little, or no backstory on what exactly the castle itself is, with there only being slight nudges such as the sacrifice chamber. It's just not enough to intrigue a player into being interested about what exactly is happening in the castle.
I haven't played part 1 yet (Actually I'm unable to because my internet hates the moddb Gamefront links), so I might be wrong on some aspects. However I cannot deny that this chapter lacks a lot of plot.
Gameplay/Scares/Atmosphere: I think the gameplay might benefit a bit better from more interesting puzzles. You did add other stuff other than keys, but most of it are just placeholders for them which are still technically just "keys". Thankfully the gameplay is fairly straight forward, and you don't have to worry too much about getting stuck. I still wish you added mementos for what the character was up to at the minute though.
There "was" an atmosphere in the story I'll give you that, but nothing really happened much besides the monster encounters that stood out in my head.
Verdict: Okay mapping which could do with several improvement mostly being in the lighting, and story sections