"Credits" are somehow converted into money in the real game. There are all sorts of strange things to find. It's all based on the data on the PlayStation disc. Whatever you see is probably in the original game but you can't get to it, or more likely this mask is the one you see placed in the wall beside the water cave.
There are so many features to implement. For example, this demo won't include another zone until I can get around to making SOM seamlessly "stream in" the data without loading screens. SOM works more like Shadow Tower in that regard. Things that seem simple aren't. Like for shields there's probably about 30 to 50 large scale details that have to programmed. Looking at it it looks simple but the devil is in the details, as they say.
Edited: Oh yes! Thanks for joining up with Patreon. I really hope it takes off. I hope others notice these comments and are less shy to take part and see others joining up with Patreon and so feel more confident. I'd like to be proven wrong that no one believes in King's Field. My hopes so far have been pinned on people who don't even know about it because significant interest and support from King's Field fans hasn't happened so far.