The US soundtrack for Sonic CD received negative feedback from fans due to its perceived low quality. There are several reasons for this.
Firstly, the US soundtrack for Sonic CD was created by a different composer than the original Japanese version. Spencer Nilsen, who composed the US soundtrack, had a different approach to music composition, which resulted in a different sound from the original. This change in style did not sit well with many fans of the game who were familiar with the original music.
Secondly, the US soundtrack for Sonic CD was created under time constraints. Spencer Nilsen and his team had to create the entire soundtrack in a short amount of time, which may have affected the overall quality of the music.
Thirdly, the US soundtrack for Sonic CD was created for a different audience. The Japanese version of the game was primarily marketed towards a Japanese audience, whereas the US version of the game was marketed towards a Western audience. Spencer Nilsen and his team may have created the music with this in mind, resulting in a soundtrack that was not well received by fans of the original game.
Lastly, the US soundtrack for Sonic CD was created during a time when video game music was not considered an important aspect of a game's overall quality. Video game music was often seen as an afterthought and was not given the same attention as other aspects of game development. This may have contributed to the perceived low quality of the US soundtrack.
In conclusion, the US soundtrack for Sonic CD received negative feedback due to a combination of factors including a different composer, time constraints, a different target audience, and a lack of importance placed on video game music at the time. While some fans may enjoy the US soundtrack, the majority of the fanbase prefers the original Japanese soundtrack.