The most accurate description of Zombie Sam's aesthetic has to be The Nightmare Before Christmas. That goes beyond artwork and frequent covers of music from the movie to being more of a mission statement. Even some of the bell-like instrumentals remind me of the holiday Haunted Mansion at Disneyland. Check out "Through the Looking Glass" for an example of that.
Not all of the music sounds like it was played on a celesta. There are driving guitars and definite rock. My favorite of the rock songs was "Woman in White".
(No, I don't think all of the song titles are literary references, but there are at least a few.)
The band can definitely be appropriate October listening, and fits well in that realm. This includes a couple of collaborations with Sophia from Season of Ghosts, reviewed last December. "Awake" is a good example of that, and of the band's more haunted elements.
If you do not care for supernatural dreaminess, it could prove distracting. Try listening to "Stay Away from Me" as an example of Zombie Sam's rock.
If you don't like any of the four tracks mentioned, they are probably not for you. If you like some but not all, you can pick and choose.
And if you like all of them, including the instrumentals, you may have just found your new perfect band in plenty of time for Halloween.
Good luck on this Friday the 13th.