Plinko is a browser game. When a page offers a download, the useful step is to work out what the file is before deciding whether to want it.
The game does not require it
Every mainstream Plinko implementation runs in a browser on desktop and mobile alike. There
is no version with better odds behind an installer, because the engine is the same one the
browser loads.
What download pages usually offer
An operator's application package — a casino client that includes Plinko among many
games. Legitimate when it comes from the operator's own site.
A free offline game using the Plinko name, with no wagering. Harmless and unrelated
to casino play.
Files claiming to predict or influence results. These cannot work: the outcome is
fixed by a seed pair before the drop, as the fairness mechanism
demonstrates. What they can do is carry something unwanted onto the device.
A short checklist
Is the source the operator's own domain?
Does the page name a licensed company?
Does it claim any advantage over the browser version? If so, that claim is false.