Catching Carmen herself

For most of a playthrough you chase Carmen's V.I.L.E. henchmen, never the boss. Carmen Sandiego herself is the series' endgame, the reward for climbing the entire promotion ladder, and catching her is the hardest thing the games ask of you.

You have to earn the case

Solving cases promotes your detective up through ACME's ranks, and every game in the series has its own ladder. The original Where in the World keeps it short: five grades, from Rookie at the bottom to Ace Detective at the top. The longer ladders people remember — Gumshoe up through Super Sleuth — belong to the later titles, Where in the U.S.A. among them. Whichever game you are in, Carmen only takes the field once you have reached the top of it, so there is no shortcut: you grind the promotions first.

Her case is harder by design

When Carmen finally appears she runs a longer, tougher trail than a henchman: the clues are less forgiving and the margin for a wrong flight is thinner. Everything you learned earlier, cross-referencing destinations, building a precise warrant, never wasting travel, now has to be done cleanly with no slack in the clock.

The warrant rule still applies, and matters most here

Carmen is just another name in the suspect database, but she is the name your warrant must carry to the final city. Catch up to her without a warrant in her name and she escapes like any other crook, except this time you have spent the whole game getting here. File the warrant for Carmen Sandiego the moment the traits point to her, then close the trail. Put her away and you have beaten the game.