I got it. Its not subtle but when I thought about it was a nice way of showing the only one theme and the title is perfect.

Only one room, only one healthbar, only one enemy.

But it would need a lot more polish, just something like getting the background to not be default blue is something that would make it a lot better.

Design 1/5 

Its very little when it comes down to the gameplay. 

Adherence 5/5

Got to say it was fitting well with the theme

Originality 3/5

It is very original to share your health with your enemies although the gameplay is just about getting to the door over and over again and less focused on the healthbar

I tried to play the game but it keeps giving me an error. Am I missing something?