To clarify, I find it hard to do anything, even video games or watching a movie, for 30 minutes at a time these days. I played a lot of M+R in the last few weeks, but not like marathon 2 hour sessions or anything. Though I would get back to it later that same day, so that’s the difference, I suppose.
This is so optional as to be something I rarely did. The only thing worth finding int the wild are orbs, and those are worth looking out for, but I never felt compelled to run around and unlock stuff I’d walked past before. It took too much time, so once I wrapped world 3 I only focused on the secret level because that led to more fights. I still had almost 1,000 orbs per character to spend, by the end of the game. I like that someone CAN do all that extra stuff, but it really isn’t “content” per se, except the secret levels.