I watched Homunculus while having breakfast on my day off, knowing almost nothing about the plot or the cast.
I knew it was a pretty popular manga so I gave it a try because lately I'm into live action adaptations.

The plot is not that easy to follow.
Long story short: an homeless guy who suffers from amnesia gets involved with a medical student who believes that if we make a hole in the middle of our forehead we can see things that other people don't. The main character has to live with this hole in the head for seven days to prove to the medical student that the experiment was a success.

The first half of this movie was brilliant.
Narita Ryo character ( God bless his acting skills) is weird, it catches your eyes from the very first time it steps on the scene.
But, towards the end, the plot get all messy.
There's a huge plot twist but it was all rushed up.

In the end, I might say that you can enjoy this movie just for Narita's character.