Does Gallery support landscape and portrait mode?

Yes, Gallery Supports both, Landscape and Portrait mode. In fact, it also supports Square mode.

How this is different than other Galleries?

It is way faster than other galleries, we also do not impose any limits on features or galleries - anything. 

How many columns are possible?

At the moment it is from 1 to 12. We have some galleries built to display this. Find it in menu above.

What happens when you click on image?

Gallery supports both - link on image and a lightbox. 

Awesome Gallery