A Deeper Kind of Slumber moves Tiamat even farther away from traditional heavy metal, with synthesizers dominating the arrangements and Johan Edlund doing completely away with metal growling in favor of an unearthly croon.

Although it's not very metallic, the music is quite heavy in its own way, creating a numb, sleepy ambience that feels both introverted and resignedly pessimistic; perhaps this is due to Edlund's conceiving the album at home with little outside input, and his relationship difficulties at the time.

A Deeper Kind of Slumber is perhaps a cut below Wildhoney in terms of consistent listenability, but Tiamat certainly cannot be accused of refusing to develop or experiment.