I think this is a great idea, but the execution leaves much to be desired. Of the 10 different slide rule models included, only one is legible. These are basically astonishingly blurry photographs of various slide rules.

The slides move, and the cursor moves, but the cursor is difficult to grab because it has no handles. You have to try to grab the thin red line itself. Very annoying.

On my computer (dual G4 @ 1.25 mhz, OS 10.3.9), the file menu doesn't work. I don't know whether that's just my set-up or not. But, once you close the slide rule window, there's apparently no option to open it again. You have to quit the program and launch it again.

I'd say this developer got tired of the project and instead of throwing it away as he should have, he released it as it is. Out of five mice, I'd give it one severed hind leg.