Mega Man Zero/ZX Legacy Collection was on display at PAX West, which is where the videos above came from. These videos also provide us with some new details on the game, as well as a potential concern.
First up, we've learned that there are two voiceover options in the collection. You can go with the original voices as heard in the games' original releases, or audio "mastered" audio that comes straight from the voice recordings. When it comes to the actual words being said, ZX will have the original Japanese voices regardless of settings, and Advent sticks to the English dub with no option to change it.
As you know, Mega Man ZX and ZX Advent appeared on the DS, which had a second screen. This will be replicated on the Switch via using the right stick, which lets you access the content that appeared on those second screens.
As for things that aren't confirmed, there's one good and one bad. On the good side of things, it seems like all of these titles might actually be included in one game card for Switch. People were instantly concerned when they saw a collection from Capcom, as they worried some games would be download and others would come on the game card. If the way the games were presented at PAX West indicates what to expect, then we should be getting all games on the game card, as Mega Man Zero/ZX Legacy Collection is basically one "game" that gives you access to all the titles.
On the bad side of things, there's some worry about potential lag in the Switch version. I want to stress that this is not confirmed in any way, shape, or form. While what you see in the image above certainly shows lag, that could have something to do with the TV itself, or the game still being in development. Don't get worried yet, but it's something to keep an eye on. We'll reach out to Capcom for comment on the matter.