• śailān-utpāṭya — tearing up mountains
  Utpāṭya is the same verb used of Hanumān lifting Droṇagiri in the Rāmāyaṇa to save Lakṣmaṇa. Dvivida — a vānara of the same lineage — has the same brute capacity but uses it to crush kingdoms, not to save them. Identical śakti, inverted intention.
• ānartān — the province of Ānarta
  The region surrounding Dvārakā on the western seaboard. By naming Ānarta the poet locates Dvivida's malice geographically near Kṛṣṇa-Balarāma — setting up the confrontation that the chapter is building toward.
• mitra-hā — the killer of his friend
  Compound: mitra (friend, Naraka) + hā (killer) — i.e. Kṛṣṇa. The asura sees Bhagavān only through the lens of his slain ally; he cannot see Hari as Hari. Gauḍīyas note: the asura's vision is the mirror-image of the devotee's — same Lord, opposite recognition.
• hariḥ — Hari, Kṛṣṇa
  From √hṛ (to take away). Hari is the one who removes — sins for the devotee, demons for the asura. Whichever way one approaches, He takes something away; only the devotee consents to the taking.
• samacūrṇayat — pulverized, devastated
  Causative of √cūrṇ (to grind to powder). The same word will return inverted in verse 23, where Balarāma cūrṇayām āsa Dvivida's stones — the demon's signature gesture is what the Lord finally turns back on him.

• Bhakti Marg Sw SB 10-67-04-11 - 2015-06-11 ISKCON Alachua
  His Holiness Bhakti Marg Swami· 2015-06-11· English

An enemy of the king will tear at the king's own province first — Ānarta, where Dvārakā stands, is where Hari resides, and so where the demon's hate points. The asura's compass always swings toward Bhagavān's dhāma.