These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Scrappy Mechanic: For solo mode, switching. This wouldn't be a big deal, except for the fact that the shoulder buttons are notoriously weak on the DSi line, leading to many deaths when switching at critical points fails to work.