Death can be useful; it's an interesting title and after playing the game it is totally justified. Starting from the main concept, I think it is not bad at all.
After playing the game I mostly got what I expected to get from it. You already know about the graphics. As I said before playing the game, adding some characters would be more interesting. Some enemies for example. Consider adding weapons (for player); even if you don't, running away from enemies would be interesting too. I like the concept of limited time and it should not be changed. Also consider adding special effects. At the point the game is you need to find some ideas yourself, make updates and get feedback to improve your ideas.
I don't know what the story is going to be but I'm curios to know after you make full one.
As trota68 said I noticed the same thing. I have noticed it on my work with Unity too and it occurs when reflections is checked as active on the material properties. Haven't found a way to fix it yet.
The game crashed after the scene was loaded. It only happened once and I couldn't recreate.
Hope I helped you