It’s a well-kept secret that the WiiWare version of Dr. Mario is one of the greatest online multiplayer games ever released on a Nintendo system. The series may have originally launched on the NES back in 1990, but it was that release of Dr. Mario & Germ Buster (AKA Dr. Mario Online Dx) on the Wii that absolutely nailed it.

Ever since then, we’ve been hoping for a sequel to kick things up a notch. Subsequent Dr. Mario games on Wii U and 3DS also included similar online multiplayer modes, but far fewer people played them and so trying to get regular matches was about as reliable as trying to get blood from a POW block.

So, here we now have Dr. Mario World, Nintendo’s attempt to take its ‘other’ puzzle game – the one that always stood in the shadow of Tetris – and see how it fares on mobile phones. And while the main focus from most of the critics will be on the single-player mode and the fact that it behaves more like a ‘typical’ mobile game than any other Nintendo release to date, it’s the online multiplayer that will quietly take over your life.

Let’s look at that solo mode first, though. Anyone familiar with the likes of Candy Crush Saga will at least recognise the general structure here: the aim is to make your way through over 200 stages, fulfilling the (usually straightforward) task in each, collecting various goodies along the way. In this case, it’s usually coins, which can be spent on other heroes and supporting characters.

The gameplay isn’t quite the same as the other Dr. Mario games you may be used to. If anything, it’s more similar (though by no means identical) to the Virus Buster mode seen in more recent versions of the game, where you use the touchscreen to drag pills around. The pace here is deliberately slow: rather than constantly throwing pills at you and forcing you to turn them as they fall, you’re shown your next pill and essentially have as much time as you need to analyse the situation and decide the best place to drag it over.

You can even ‘snap’ pieces past walls and other obstacles, which gives you far more freedom than you’d usually expect from a falling block game. This also extends to spare pieces; whenever you make a match of three or more, any extra blocks that start to fall can also be grabbed and moved wherever you see fit. This can lead to some satisfying combos where you’re clearing entirely different sections of the play area with a single move.

Although the standard aim is to remove all the viruses on a screen, there are a handful of variations dotted around to mix things up a little. You may be asked to collect all the coins on a stage by performing clears right next to Mario-style brick blocks; some of these contain multiple coins so you have to find a way to hit numerous clears without using too many of your limited supply of pills. Other stages give you a time limit, which punts the whole ‘take your time’ mantra into the sea and has you frantically rubbing at the screen like a finger painter who’s just woken up and is trying to realise his vivid dream before he forgets it. Which is a comparison we’re sure you can all relate to. Ahem.

Initially starting off as Dr. Mario, it isn’t long before you’re offered the choice to either stick with him or switch to Dr. Bowser or Dr. Peach (you’ll get the chance to unlock the others later). Each doctor has their own special move that’s triggered when you fill a gauge; Peach, for example, chooses a random column and wipes out everything in it. As well as this, you can spend your coins in a ‘staffing’ screen, which lets you unlock more doctors or (more likely) supporting characters; you can apply up to two of these to gain extra bonuses while playing.

These doctors and characters all have the same likelihood of being found (something like 2.8%) so there are no ‘rare’ ones – at least not yet. Although it’s essentially a loot box system and you can get duplicates, these level-up your existing character to make their abilities more potent. Once the character’s levelled-up to the maximum, they are removed from the pool of possible characters in the loot boxes. To Nintendo’s credit, then (to an extent), this means you won’t be in a situation where a loot box provides a truly useless character, and apparently (full disclosure: we haven't been able to verify this ourselves) once you’ve unlocked every character and maxed them out, the loot box option is greyed out and can no longer be used (at least until Nintendo adds more characters in an update)

And so we come to the elephant in the hospital: the microtransactions. Nintendo’s already tried going down the noble mobile route with Super Mario Run’s ‘pay $9.99 and get everything’ structure, but since it didn’t do quite as well as it had hoped, subsequent mobile games from Nintendo resort to the more common free-to-play mechanics you’re probably used to. They’re also about as cookie-cutter as it gets; its premium currency is diamonds, which can be bought with real money and used to buy coins (which get you new characters), hearts (which give you energy to keep playing) and other general power-ups, like extra turns in a stage and the ability to wipe all your pills off a level.

You need to pay real money about as much as you would in Candy Crush Saga. Your five hearts essentially act as five lives: beat a stage for the first time and you’ll be rewarded with a heart on top of your other bonuses, meaning as long as you continue to progress through the stages you’ll be able to keep freely playing. It’s once you get to around level 30 or 40 that it starts getting difficult enough to sap away at your lives, and this is where you may feel a little frustrated that after your five hearts run out they each take half an hour to replenish. Of course, for 30 diamonds (around £3) you can buy the option to play with infinite hearts for an hour – but please don’t do that. That’s silly.

How this affects you, then, depends on how you play your mobile games. If – and forgive us for being so blunt – you’re very much a lavatory-based mobile gamer and only plan on playing in little 5-10 minute bursts, then you’re likely to never be affected by the energy situation. If you take your time and play strategically – which is recommended if you actually want to clear any levels – each stage can take a couple of minutes to either clear or lose (when you run out of your allocation of pills). If, however, you’re the sort who likes hour-long stints on your phone while the telly’s on or what have you, you may quickly become frustrated at the constant nickel-and-diming. It’s purely hypothetical, but we wonder how many people would have done a Super Mario Run and paid $9.99 for unlimited access to the solo mode here.

There’s one other element still to be covered, though, and that’s the online multiplayer. This is very much the secret weapon of Dr. Mario World, and the place to head when your lives run out. It has you taking on other players in real-time as you both try to clear as many viruses as possible. Every time you clear a certain number you’ll force more viruses onto your opponent’s screen, so the faster and more accurate you are, the harder you’ll make it for them. It’s obviously about as simple a concept as it gets, but given that the single-player mode is all gems and hearts and coins and power-ups, simple is exactly what we’re looking for here.

Best of all, the online multiplayer doesn’t have any energy system whatsoever, meaning you can play it forever without ever having to cough up any money. Each win also earns you some coins (albeit not many), which means you can still grind your way towards unlocking more characters. In fact, the only thing stopping you in this mode may be your phone’s battery.

This may differ depending on your model, but our Pixel 2 XL dropped about 50 percent of its battery in an hour of play and became warmer than a grandparent’s cuddle (if that grandparent was also on fire). Be wary that if you’re planning a long multiplayer session you’re going to want to have your phone plugged in, and even then be sure to keep an eye on its temperature. It’s not quite clear why it’s such a battery drain on some models – it’s Dr. Mario, not Doom – but hopefully, future updates can identify and fix it.

Conclusion

Dr. Mario World is very much a game of two halves. The single-player mode is fun in short bursts and short bursts only: lengthier sessions are impossible without regularly dropping real cash on it. Meanwhile, the multiplayer is an unrestricted delight, and the steady stream of available players means it could become your next obsession. Most importantly, both modes are built around a legitimately entertaining touchscreen twist on the standard Dr. Mario gameplay that makes plenty of changes, but clever ones that take the mobile format into account. It isn’t proper Dr. Mario, then, but – assuming you can keep your wallet in your pocket – what it is isn’t half bad.