One can't deny that this is the mother of all oldschool adventures. It is heavily based on puzzle-driven interaction by manipulating objects, which is very contrary to my own way of writing games based on progress levels that cause further moving on in a linear story. Which is not a bad thing, just a different approach. What you did here is a solid effort that draws lots of inspiration from the 80s counterparts and therefore pretty much comes with lots of vibe those games were famous (and also infamous) for. I think Chris will enjoy this game very much.
Personally I liked playing it, even though I would like to mention a few things that I encountered "along the way":
1) Backpack: when you try to EXAMINE it, it tells you what's inside, which is fine. When you then try to LOOK INSIDE BACKPACK the game tells you that "The backpack is not a container." which is very confusing for the player. I'm guessing this is the standard Adventuron reply to an object that really is no container, so my suggestion is that you override this reply for the particular object to avoid any confusion.
2) Maze: inside the house, navigating to the different locations had a very maze-esque look and feel. I don't like mazes in adventures so that was not my cup of tea. I also felt that if you do a maze, you could maybe make the pictures a bit more different than just changing colours. I know this is too much to ask for in the time we had, but the identical pictures hardened the maze feeling in me.
3) Objects: Personally I felt overwhelmed by the objects you need to interact with. This is generally not a bad thing. For people who are into object puzzles, this can be heaven. I for myself found it hard though to see the "masterplan" in-between all those objects. I also have a feeling the amount of "red herrings" is too high in this one. Again, nothing bad with red herrings, I have one in Rabenstein too, I'm just reflecting my own preference and experience when playing the game. The last thing I'd like to mention regarding objects is that I felt with the massive amount of objects you can interact with, the limitation of items that could be carried felt like an unnecessary extra level of difficulty. That I was still wearing a backpack (which was not suitable to put some things in) didn't force me to cheer when the message that I'm carrying too much stuff appeared :D
Anyway, this is a very nice oldschool effort and without doubt you put much work into this, which you can feel when you play the game. It needs to be mentioned that I also loved the graphics. They didn't feel like quickly made, they actually felt very polished and give the game a professional look. I'm absolutely looking forward to your future efforts!