Mario Kart DS
I love the Nintendo DS and it has been blessed with a growing mountain of great, interesting games, but it has lacked a killer app to point to and say "here's why this is such a great system." Mario Kart DS is the system's Halo. Its Soul Calibur. It's the best in the series and its new tweaked rules and weapons, incredible track design, and multiplayer content make a stunning package that no DS system should exist without.
Slipstreaming, the most substantial addition to the core gameplay, introduces an excellent risk/reward component to the series. Tailing another driver is typically a dangerous practice in Mario Kart games; most items can be dropped behind characters to force any tailgaters to spin out. In Mario Kart DS, driving in a character's wake provides a moderate speed boost. Remain there a few moments, and you're rewarded with a larger boost that often slingshots you in front of the character you were tailing.
There aren't many changes to the weapon lineup, but many of the best weapons of Double Dash!! have been refined and revisited and are now available to all characters. The Chain-Chomp has been brought back as the Bullet Bill. Wario's Bob-omb is back as well and is extremely devastating when dropped behind.
The single new weapon is the Blooper, a squid that will shoot ink on all your opponent's driving screens, forcing them to drive with the "map" screen displayed at the bottom. While the weapon is mildly annoying, it does get the player looking at the bottom screen. Driving on the map screen becomes surprisingly comfortable with a little practice. The map screen also lists what weapons characters have; useful knowledge when attempting to slipstream safely.
There's 32 racing tracks in the game; half new courses, and half "classic" courses from previous games in the series.
The new race tracks in the game are an excellent group, without a dud in the lot. There's a number of new creative tracks. Waluigi Pinball has players racing through a neon pinball machine while someone is playing it, trying to avoid being crushed by giant pinballs and avoid getting knocked about by the flippers. The Tick-Tock Clock track involves driving through the mechanisms of a giant clock with huge turning gears that serve as driving surfaces. Peach Gardens has players zipping about a giant hedge maze, encouraging the use of the map screen to find the best route and avoid wandering chain-chomps. Many of the other tracks are customary entries, but are often the best iterations of their type. (Particularly Wario Stadium, Bowser's Castle, and Shroom Ridge, the new highway course.)
The classic courses are a bit of a mixed bag; not all the courses have aged well and they suffer by being listed directly below the best set of new tracks the series has seen. The SNES and N64 tracks have aged the worst. SNES tracks flat, simple, and sometimes punitive designs (like the deep water pits in Koopa Beach 2) reveal how far we've come in 14 years. The N64 tracks destroy any nostalgia toward Mario Kart 64; the tracks are frighteningly uninteresting and ugly. (OK, Moo Moo Farm is still fun to play, but that's it.) The tracks plundered from Double Dash!! and Super Circuit feel much more modern (duh) and are largely great to play.
I'll discuss multiplayer, specifically playing over Nintendo's Wi-Fi network, in an upcoming post. It's largely well implemented but with some aggrivating quirks. Regardless of any quirks, it's always fun to race other people and even if Mario Kart DS didn't have multiplayer, it'd still be the best game on the system.