I see
The fun thing about Metal Slug IMO is, that you can either play it by just bashing through the enemy hordes and getting to the level exit or have a more 'tactical' approach (regarding ammo and like you said bonus items). Over the time you refine your way through the levels slightly. I haven't really played to gain the most points before (tried to save all prisoners several times though), but getting over a million means that you really have to make a perfect run
Quite impressive score Cliff got there