As is indicated in its title, this track has two sections. Pt. 1 (0:00-11:42) has a slower tempo and progressively evolves, the percussion and guitar melodies gradually building and intensifying while synths drone in the background. I think this section bridges perfectly into Pt. 2 (11:42-16:21), which is faster and has a more urgent sound driven by distorted riffs and energetic guitar leads.
King Buffalo have also included a “radio edit” for Pt. 2 of this track on their Dead Star album, and I think that this “movement” of the song sounds great on its own as well:
This track begins with an introduction section (0:00 - 2:08) featuring only acoustic guitar and vocals, which has a distinct melodic progression compared to the middle part of the song (2:08 - 14:50). The middle section includes both acoustic- and electric guitar, bass, drums, and vocals; and while it shifts considerably, exploring multiple themes throughout the section, I think that as a whole, it sounds more like rock music than does the intro, which sounds to me more folk-inspired. Then there is an outro, a sort of reprise of the introduction, which nicely concludes the track (14:50 - 16:01).
There’s also another version of “I’m the Mountain” from Stoned Jesus’ Seven Thunders Roar (Anniversary Deluxe Edition) album, without the intro/outro sections; and I think it sounds great as well in its own right: