You can apply the same behavior as described above to the grid layout for an event too.

Starting with Event Gallery 5.4.7, you can use the Breakpoint editor to add breakpoints to your site. This will generate CSS automatically.

Just add the necessary media queries and use the following CSS selector. The principle should be pretty clean and is easy adaptable to the tile layout.

.eventgallery-tiles-list .eventgallery-tile {
  width: 100%;
}