Holy moly; that
has to be the game I'm thinking about!!!
I just fired up fs-uae and ran this game with an Amiga 500 configuration & the music brought me back to maybe year 2000-2001 with an Amiga 500 I had way back than (bought the Amiga from a classmate for almost nothing, I had to get rid of it later on because it ate floppy-disks for dinner).
My memory is kind of fuzzy, but personally I don't remember the giant worm attacking you. Maybe I had an even earlier build of this game with even less features stored on a Demo disk, but it could also be that I had forgotten all the details.
I remember having visit of an old friend way back then, and he was playing the first Age of Empires on my secondary PC. I found this game on a disk, saw that the game supported 2 players simultaneously, asked if he'd like to join the game and he said "nah, I'm fine" (he'd rather play some more Age of Empires 1 than this old game)
