Is it possible to play a game downloaded from the internet, on MicroSD card on Nintendo 3DS?
To answer your exact question, No. The Nintendo 3DS has a SD card slot but you can't store games downloaded from internet on the default SD card which is used to store content/demos downloaded from the eshop.However, you can find Flash Cards online like R4i/Supercard which fit into the DS card slot of the 3DS and which need a microSD to function. You need to save ROMs downloaded from the internet (One 3DS game per microSD card last i checked, unless this limit has been bypassed in recent times) along with the Boot files for the card (available on the retailer's site) to operate. But be warned, Nintendo aggressively blocks Flash card hacks with every system update which might require you to keep updating the Boot files of the Flash card on each microSD card that you plan to use.You can find more detailed information online (gbatemp is a very good place that'll answer most of your questions) .Hope this summarized answer helps.
Can you trade Pokemon between a Nintendo 3DS and Nintendo 2DS (specifically Pokemon Sun and Moon)?
Ask yourself this - can Pokemon Sun and Moon trade between each other?The entire 3DS family uses just about the same coding, except some of them are larger, have extra buttons to randomly press, or are slab-like. So the actual device doesn't matter, as long as it is within the 3DS family. The 2DS is part of the 3DS family. All that matters is if the games are compatible with each other to trade. And, as of 12/29/2017, the last I checked, they are indeed compatible.
How would you make the Nintendo Switch better?
Personally I’d incorporate a higher capacity battery so it lasts longer whilst playing in handheld mode, i’d also improve the memory by adding a SSD even if this did make the console larger it would be worthwhile. Along with these I’d try to redesign the console so it fit into your pocket whilst in handheld mode. I think the clamshell design of the 3ds would be absolutely perfect for this with joy cons that connected to the dock rather than the screen. This way I genuinely feel it would be ideal as you could still have controls built into the clamshell and you could still use those controls or the ones connected to the dock whilst the console was in tabletop mode. The lower part of the clamshell would also act as a stand for tabletop mode. Incorporating 3ds support would also be a must have feature but only for when the console was in handheld mode. Like this people would only have to buy 1 console to play Nintendo games at home and on the go. Nintendo would still be able to sell 3ds consoles, and games and people could play both types of games without having to buy/carry 2 consoles around.
Will an American 3DS game card work on a European 3DS?
The answer to the question is: no. Nintendo has a region-lock on the 3DS that prevents you from playing out-of-market games, even though there’s no technological reason.There are solutions to your dilemma, however:You can import an American 3DS, which of course will play American 3DS games. The more American games you need to import, the more economical this option becomes.You can soft-mod your 3DS to disable the region lock. This requires some technical expertise, and of course is going to void your warranty. If your 3DS is old enough to already be outside its warranty period, however, that may be a moot point. There’s also a risk of bricking your 3DS if you do something wrong, but there are dozens of guides on the Internet to follow.You can buy a pre-softmodded 3DS. This is not a very good option, since it costs just as much as option 1 and doesn’t give you anything you couldn’t do yourself for free with option 2. These aren’t worth the money, in my opinion, because the skill threshold needed to do your own soft-mod is not as high as you probably expect.A note about soft-modding: as the name implies, it is a software-only approach, which means no soldering or disassembly required.