Don't know what a "zamak" is but the alumium slide looks just like the 9mm slide. If it shoots as well as it looks, I will be tickled. So much better than the Marvel conversion I have with a larger 1911.
Zamak/Zamac is a family of zinc alloys sometimes used in firearms manufacturing. Umarex-made products like the Sig Mosquito, Walther P22, and Walther PK380 have slides and some components made of Zamak. All Hi-Points have slides made of Zamak. Dangerously low-quality guns like those of Jennings/Jimenez/Bryco, Lorcin, and Raven have zinc alloy slides, frames, and other components.