Currently there's no obvious way to make a poke shiny in gen 2. You've got to go look up shinyness on bulbapedia or somewhere else with reasonable gen 2 info, find that "If a Pokémon's Speed, Defense, and Special IVs are 10, and its Attack IV is 2, 3, 6, 7, 10, 11, 14 or 15, it will be Shiny.", and set the IVs. Having a checkbox which changed the IVs to 10 Spe/Def/Special and Atk 15 when checked, and all 15 when unchecked, would make this much easier. Obviously not a priority feature, but it'd be a nice little touch and probably fairly simple.