Importantly meaning

More importantly, how did they get out?

More importantly, I wonder why he has it.

Dan had always been his second-in-command and most importantly, as good a friend as any of Brady's brothers.

It was apparent that Fred had skied before at some time in his long life and, more importantly, he knew enough to do so cautiously.

Most importantly, the game is often a little clunky around the edges, with little weight to your characters or actions.