"Стальное сердце" by Kurara was released on November 29, 2016. Стальное сердце is about six minutes long, preciously at 5:52, making this song fairly long compared to other songs. There is only one song in Пуля, so we believe that "Стальное сердце" is a single. In terms of popularity, Стальное сердце is currently unknown. Although the tone can be danceable to some, this track does projects more of a negative sound rather than a postive one.
The tempo marking of Стальное сердце by Kurara is Moderato (at a moderate speed), since this song has a tempo of 115 テンポ. With that information, we can conclude that the song has a moderate tempo. This song can go great with walking. The time signature for this track is 3/4.
This song is in the music key of C Major. This also means that this song has a camelot key of 8B. So, the perfect camelot match for 8B would be either 8B or 9A. While, 9B can give you a low energy boost. For moderate energy boost, you would use 5B and a high energy boost can either be 10B or 3B. Though, if you want a low energy drop, you should looking for songs with either a camelot key of 8A or 7B will give you a low energy drop, 11B would be a moderate one, and 6B or 1B would be a high energy drop. Lastly, 5A allows you to change the mood.