I love Zero Mission for what it is, which for me is a fairly linear Metroid adventure. I just don't have any interest in learning Samus' advanced moveset, and I don't think the game is very encouraging of 100%'ing the game before you fight the final boss. After the credits, I'm never interested in going back through Zebes to collect the other 40% of the game's collectibles. I always wished that more of the game's collectibles could be collected along the way. The just feel kind of designed to be collected after you power up Samus completely.