Whether one likes the The Church or not, it must be admitted that their style of music is very original. But what is it that makes the band so unique sounding? As a guitarist who has often been accused of 'playing like The Church', I'll offer a few bits on what I think it is to play 'Churchily.'
Not surprisingly, the interplay between Marty and Peter has had a lot to do with the unique sound. Koppes historically has played Fenders (teles, strats, and Jazzmasters), while Marty is well-known for his Rickenbacker 12-strings. You can hear the unmistakable chimes of the 12-string (electric and acoustic) in many songs, some which come to mind are One Day (the lead line), Laughing, It's No Reason, An Interlude, and of course, Under The Milky Way.
Many of the chord structures, at least in the early days (Heyday and earlier, roughly) were very folky. Check out Just For You, No Explanation, and Into My Hands... An example of a jingley jangley folky riff in the early stuff centers on a D-major; try going from a D chord to Dsus4, then take your 4th finger off, forming a Dmaj again, then play the high E string open, all the while leaving your 2nd and 3rd fingers in place. Pick the D/G/B/E strings or strum them quickly. Songs like Almost With You, Tear it All Away, and Bel-Air all employ this riff effectively. Also, Marty has mentioned that he flips the thick and thin strings on his 12-strings, to get a more unique sound. You'll hear lots of jangley folky stuff (especially like the D riff) on Marty's solo albums too.
The quick high mandolin sound also is popular with the guys. Sometimes a real mandolin is used (like in Metropolis) and sometimes just the style (A Month of Sundays, Russian Autumn Heart); playing fast leady chords above the 12th fret. I would be willing to bet that this style is definitely Marty's and not Peter's, judging from hearing Marty and Steve acoustically (check out Marty during the bridge buildup during Hotel Womb in the acoustic version!) It works well if you have another guitar to back you up playing regular chords down below, like Peter does for Marty.
Many Church guitar lines have lots of harmonics in them (12th, 7th, and the 5th fret if your action is not too low, and your intonation is set correctly.) You can hear this in songs like Myrrh, The View, Fly, Electric Lash, and the beginning of Happy Hunting Ground (which, incidentally, has 2 finger-picked harmonic chords, 12th fret E/G followed by 12th fret B/D strings; try it with stereo chorus and lots of reverb.) Also notice that open strings and open chords are used in many songs too (listen to the beginning open chords in Hotel Womb for a good example of this.)
Lots of the moody aspects of the guitars are obviously done with effects. To me, Priest=Aura is one of their moodiest albums, with Chaos being one of the best examples of creepy guitar sounds. Lots of reverb and whammy bar here (like during the break after the drums build up and fall away.) Stereo chorus effects are all over the place in The Church's music too, and delays also. Reptile, Dome and Now I Wonder Why all have echoey, delayed guitar parts.
Marty's use of the volume pedal is always appropriate and never overdone. Sometimes he uses it with a stereo chorus (like in Happy Hunting Ground; add delay with plenty of duration to it to get the longer, sustained volume pedal string effect) and other times without (Destination, Leave Your Clothes On) but it always sounds great. Which leads to another aspect... I would be hard pressed to ever find a guitar line (solo or rythm) that I would consider 'too busy'. The point is that Marty and Peter have a grand sense of when to not overdo it, and keep a line simple. I think you can achieve a lot more feeling and emotion in your guitar line by using different effects and tempos than playing fast Eddie Van Halen style licks. It's not how FAST you can play, it's HOW you play. Though the lead guitar does wail during Church concerts, and in songs like North, South, East & West, and Grind (especially any live version), to name a few.
Of course there's a lot more to The Church's sound than the guitar work. Being also a bass player, I could spend time going into Steve's unique style, but for the sake of this article I'll stick to guitars! Obviously the vocals of The Church have a lot to do with the dreamy quality of the band as well.... and when you get right down to it, only all of these elements in just the right doses can make up the music of The Church.