This is the 4431st most frequent German word.
immens
"Immens" means "immense" or "vast" in English.
Here, 'immens' is used as an adjective meaning 'huge' to describe the substantial magnitude of the project costs.
Die Kosten für das Projekt waren immens.
The costs for the project were immense.
In this sentence, 'immens' is again used as an adjective to emphasize the overwhelming and great extent of his passion for music.
Er hat eine immense Liebe zur Musik.
He has an immense love for music.
This usage of 'immens' combines its meaning as an adverb paired with an adjective ('groß') to intensify the description of the challenge's size.