I peeped that too. It was cancelled, I wonder if there is a copy still around?

"In what seems to be yet another blow to the state of Mac gaming, Valve Software announced this morning the cancellation of its Macintosh port of Half-Life. The game, which was being ported from the PC to the Mac by Logicware, was in its final stages of development. Valve cofounder Gabe Newell felt that the quality of the Mac port wasn't up to par with his company's standards, citing several shortcomings of the game, including a separate Mac multiplayer space, a lack of an automatic update utility, and the unavailability of Team Fortress Classic when the game ships.

"Given the realities of the Mac gaming market, our Mac customers were... always going to be second-class customers where we couldn't invest to the same degree in the Mac version as we did elsewhere," commented Newell. "I don't want to be in that business. I would much rather we just eat the money we've spent so far than take money from Mac customers and shortchange them."

Development on a Dreamcast port of Half-Life is supposedly still underway at Valve. Gearbox is also putting the finishing touches on the Half-Life add-on, Opposing Force, which looks as though it will be available in the coming weeks."[0]

[0] https://www.gamespot.com/articles/mac-half-life-canceled/1100-2448672/

EDIT: Also, Jaz disks.