A good game, but suffers from a fatal flaw, not in story, or atmosphere, but in information.
As most of those with interest already know, Blood Will Tell is based on a manga by Tezuka Osamu, also known as such titles as "the god of manga" and "the father of manga/anime" in Japan, and best known in the west for the series Astro Boy. As Gamespot's review will tell you, it's storytelling alone makes it worth playing.
As for Atmosphere, the demons are well designed, the characters are believable, and most importantly, the fear and suspense is well captured in the environments, and events. I still vividly remember certain scenes and they are executed well enough that I could picture similar cinematography in film. Though the graphics are relatively good for it's time, they are dated, and regardless I still am able to enjoy the scenes more than some more recent games.
Lastly, there is one thing gameplay wise that sets it apart from the norm. That is unique system by which every boss defeated returns a single body part, giving the player a new ability, stat, or feature. It is because of this that the gameplay in between the story don't get dull and repetitive.
Now, I've given my reasons why this game is a good game, but, there is one blinding flaw. In this game, there is a compendium of all the demons you defeat, and a short description, Sega however decided to replace the names of the traditional Japanese monsters with corny sounding English knock-offs, some absolutely terrible, like "Hell Crusher" or "Mountainous". This is a flaw because it ruins the atmosphere built up throughout the game when your bosses all have names seemingly thought up but a ten year old, based on their appearances alone, and two because it makes no sense. When playing a game set in Japan, with Japanese characters, featuring all Japanese monsters, what need is there to alter the names of only the monsters, especially when each one comes with a description. This reminds me of the early days in gaming where for some reason American and European gaming branches apparently thought no one would play a game if the characters names weren't relatable enough, and we end up our heroic savior... Brad. It is in my opinion a game ruining flaw, as it adds comedic levels of stupidity to a dramatic story.