Note to any developers resurrecting an arcade classic or two on modern download services: Final Fight: Double Impact is the right way to do it. What it lacks in sheer bulk (it's only got Final Fight and, randomly, Magic Sword), it more than makes up for with a deeply infectious reverence for all the minutiae of the arcade experience.
Everything is spot-on. Both games are here in their entirety, hookers and all. One of the graphics filters reproduces the soft edges, phosphor glow, and slight curvature of the old CRT monitors they used in '80s machines. You can play either game framed by a perfect reproduction of its cabinet art, controls and everything. Double Impact was obviously made by some people who really love old arcade games. It's glorious.
Of course, as much as you want to wax nostalgic about Final Fight and its musclebound mayor Mike Haggar, it's still just an old-school beat-'em-up. That means a lot of walking from left to right, hammering on the attack button, and occasionally busting open a barrel or crate to devour the health-restoring roast chicken concealed within. Magic Sword's fantasy hack-and-slash is similarly one-trick, and though it's merely a side-scroller, it at least gives you different weapons and allies to fight with through its 50 levels. The point is, it's great to stroll alongside these games down memory lane for a couple of hours, but they aren't deep enough to support repeated playthroughs anymore. But for $10, you might not need them to.
Double Impact's presentation does everything you'd want, and the backend features hold up their end of the deal too. There are checkpoints in both games so you can pick up where you left off, and every manner of two-player play is in here: local, online, and even a jump-in matchmaking mode that drops you into the game of a random online player. (That mode can be slightly shaky when you first join a game but quickly stabilizes and makes for a smooth experience.)
Maybe the best addition is the Vault, which ties into the in-game achievements/trophies but extends well beyond them with extra challenges like "beat this game using less than 18 continues" or "finish every level with Guy." Some of these goals are pretty rough, and make you realize how intently old arcade games devoted themselves to the goal of making you pump quarter ad nauseam. They're cheap as hell. But finishing Vault challenges unlocks you tons of great old '80s concept art, fan art, comic book pages, and other random goodies that are fun to look at if you're way, way into Final Fight and Magic Sword.
Capcom is in the enviable position of owning a huge stable of beloved old arcade licenses ripe for a 21st-century digital repackaging. It's only fitting that a game as classic as Final Fight should be first up for this kind of royal treatment, but then again, I'd be willing to play any arcade rerelease that's this lovingly restored.