Recently downloaded this off of Steam, and I've mostly been going from one level to the next level, without really exploring the grounds or finding the hidden cards and arrows, I was just wondering if I will be able to do that at the end or does the game stop being and open world once you reach the final mission ALA Prince of Persia, where I thought I would be able to find all the Orbs at the end, but the game doesn't let you do that after the last mission. So, should I explore between missions, or leave it for the end?

Hey, not sure if you need this anymore because you posted it a week ago, but collecting cards is not really that useful, you will level up enough just with figments.  Also you need to get a device that harvests like 80 arrowheads at a time at some point in order to get an important item, so collecting arrowheads (because you need it for the device) is important, but you should have enough by just picking them up when you see them.  Have fun, one of my favorite games.