OK. Had a chance to play The Sphere now. Comments as follows
Graphics - Excellent. Good-looking 3D environment that fits well with the sci-fi setting of the game. It feels like a real environment that the player is standing in, which is great for immersion.
Sound - The haunting back melody works with the isolation theme of the game. Does start to get a bit repetitive after a while. I think that is because there is only one tune and any tune is going to feel repetitive without any variety to set it off. The computerised voice is also very well done.
Story - Interesting concept but getting the entire thing in one go from the database makes it more like reading a short story. The limited environment makes this virually unavoidable so consider this as a positive comment. As long as you have the story revealed in a more interesting fashion in future then I think you don't have any problems with the content.
Movement - You've fallen into the same trap as a lot of games with node-based movement. If I'm standing at the bed the synthesis/food hatch is right next to me. However, to get to it I have to walk to the middle of the room. Having to take a wholly artificial diversion like this just reminds the player they are in a game, blowing the immersive feeling from the graphics. This is not to say that node-based movement is a no-no, but if you're going to have an open space, you really need to have open movement in it, at least to adjacent nodes.
Interface - The interface is nice and simple. This has both advantages and disadvantages. The big advantage is that it makes the game easy to play. I could wander around and interact with things without needing to read a long manual. The flip side is your interaction is limited. You can only do one thing with any interactive object. Because this is such a small game, there isn't really enough interaction to tell if this will make your future games too simplistic. There are many good precedents for single-click play so I'll reserve judgement.
Gameplay - As you intimated in your opening post, it is very difficult to work out what to do. I wandered around the small space, used the computer to synthesise all the food (collecting each from the hatch) and read the database. After that I wasn't really sure what else to do. I wanted to try to do the recommended exercises but couldn't interact with the floor. I wanted to try out the bathroom facilities but that was a no go. I wanted to try to combine the foods I'd synthesised but there doesn't appear to be an inventory to allow that. This may be solely because this is a test-piece that was made in two weeks (so this is all there is to do). If not, you need to give the player some better hints on what to do.
Incidentally, is the game saved in some sort of test mode? With no manual I took to experimenting by tapping random keys when I got stuck. Various options changed the field of view, resolution and other operational features. More importantly C caused the interactive portions of the game to highlight (revealing two additional sections near the bathroom door which I couldn't get to work).
Definitely leaves me interested in seeing more from you though.
