The Dr. Mario series' has always provided great puzzling action despite its no-frills design. Conceived during the 8-bit years, when Tetris had recently exploded on the scene, Dr. Mario stood out for its peculiarities. In the first proper 3DS installment in the series, Dr. Mario: Miracle Cure, the formula is tweaked ever so slightly, providing you with something new to try even if you spent far too many hours playing the original version on the NES or the bite-sized chunks that appeared more recently in the NES Remix series.

Despite the adjustments, the core design remains intact. You still move colored pills as they fall into the play area, flipping them around in an effort to line up four or more pill segments and viruses of the same color. Find success, and maladies and medicine disappear, leaving you with more room to maneuver. You win when all the nasty bugs are gone, or you lose if the rising wall reaches the top of the screen.

The "Miracle Cure" part of the game refers to special new power-ups that now appear by default. These drop periodically once you fill up a meter that rests alongside the play area. There are four types. One variety looks like a bomb and vaporizes anything within range once it lands. Another is V-shaped. If you match it with several pills or viruses of the same color, everything on the screen that matches that hue will vanish. A circular capsule with a “C” engraved on it wipes out all its brethren but leaves the viruses in play. Finally, arrow formations eliminate all objects in a horizontal row, a vertical column, or a cross pattern.

Nowhere are the miraculous power-ups featured more prominently than in the game's new mode, Miracle Cure Laboratory. It presents 50 puzzles that ease players into the game's design, and you can use the tutorial option if you need more assistance. The available stages are quite fun, particularly because some of them force you to play in ways you otherwise might not try. A few of the challenges are genuinely puzzling, relying on more than just twitch reflexes as you get rid of virus clusters. For example, you might need to stack pills in a column so they reach the same elevation as a series of vertical arrows and then drop a horizontal arrow in place so it eliminates and activates those other arrows. It's a shame there aren't more puzzles available, though. Even a middling Dr. Mario player probably won't require more than 3 or 4 hours to conquer them all, which just doesn't feel like enough when every other mode borrows so heavily from past house calls.

The game's title doesn't make it obvious, but Mario isn't the only physician on the scene. Luigi also returns for an encore performance, following his 2013 starring turn in Dr. Luigi on Wii U. The lankier brother throws pills that are stuck together in L-shaped formations. Dealing with them requires a different sort of planning because the combos that are a good idea when Mario hands out doses are now practically required. If you can’t think a few steps ahead, you're in for a bit of trouble. It's fun for a few rounds, but also exasperating compared to Mario's more conventional treatment, because a run of unhelpful pills turns into a disaster twice as quickly.

Outside the Miracle Cure Laboratory mode waits the Custom Clinic, which you can configure as you see fit. Here, you can choose between Mario and Luigi, depending on which pill formations sound the most interesting at the time. Then you can either compete against an AI opponent or a wall of viruses that slowly rises as you place pieces. If you go with the former option, things can get frustrating if you don’t play quickly. When the AI makes a lot of matches in short order, you must deal with handicaps. Blocks suddenly might refuse to turn, or pressing left on the d-pad might make a block move in the opposite direction. Such effects only last a short while, but they make things difficult in a way that extra debris does not. That's not necessarily an improvement, but at least it's different.

If you're looking to enjoy an experience that precisely matches the old NES game, you're out of luck. The Custom Clinic is as close as you'll get, but there are some differences. You no longer have the option to start with only a few pills and then advance from stage to stage, which at one time was standard in a number of Nintendo's puzzle games. If that's how you want to play, you're better off turning to Dr. Mario on the Virtual Console.

Much like Luigi and his wonky capsules, the Virus Buster mode appeared previously in Dr. Luigi. In this mode, the player holds the 3DS sideways and uses a stylus to manipulate pills instead of the d-pad and face buttons. The action's pace slows substantially here, and it needed to. Flipping and dropping pills with a stylus doesn't feel nearly as intuitive because it's easy to accidentally flip a pill when you intended to drag and drop it. That kind of mistake can ruin your whole game if you aren't allowed at least a split-second to recover. The slower pace also allows multiple pills to eventually start dropping at once. You can move them around in any order you like or even grab falling debris to set up combos on the fly. It's an interesting switch from the norm, and things get fairly frantic on the higher settings, though Virus Buster doesn't lend itself to lengthy sessions in the way that classic Dr. Mario modes do.

Multiplayer modes make up for most of the ancillary modes' shortcomings, at least, and could go a long way toward keeping Miracle Cure in heavy rotation if you have interested friends. You can play locally with a buddy (Download Play is offered in the event he or she hasn't purchased the game and doesn't mind you choosing the rules that govern play), or you can battle on the Nintendo Network. In either case, you have your choice of doctor, and Miracle Cures can be disabled if you prefer, though the lack of stage progression keeps this option from allowing a proper replica of the original Dr. Mario. When you play online, rankings are tracked for each different setup, which should keep things competitive if enough people play. Currently, though, the online scene is rather barren.

Considering how long Dr. Mario has been around, the modifications here serve as a pleasant surprise and manage to inject a fresh element into a puzzling experience that is by now a bit long in the tooth. Even without the new content, Dr. Mario: Miracle Cure is a worthwhile addition to the serious puzzle fan's gaming library. It just doesn't offer enough that's new compared to Dr. Luigi to warrant a glowing recommendation if you already invested in that other recent release.