NES Classic runs at 60 fps (which is .5 slower), and Wii VC (which you'd have to buy a Wii which already has it bought since Wii Store closed down) is much more slower
You could find an original NES in the USA for much cheaper than the Classic as far as I know.
What @LeonD011 said
You can find original NES consoles on Facebook Marketplace, Craigslist, Retro Game Stores (in the middle of the US, there's a store "Vintage Stock", but others in other areas of the US)
Good quality NES console with controller and Mario/Duck Hunt combo should be around $100 give or take iirc.
You'll also have to procure a CRT tv - otherwise you'll have a LOT of input lag (if you plug the original NES into a modern LED tv)
That being said - unless you're wanting to buy a console out of principle, or plan on running into the sub-5 range... Wii VC or NES Classic may be an easier and more straightforward option.
Both of the above DO run at 60fps instead of a smidge under (original framerate), which will lose you a half second over a 5 minute run. However, if you're wanting to run it and aren't planning on REALLY pushing the speed to the limit - a half second doesn't really matter much. Milliseconds aren't even included until 5:02.x anyway.
The FREE option is to run it on emulator... and the framerate will be the correct framerate. The downside is that there's existant input lag, and it's not "original" if that kind of thing bothers you - but there are plenty of runners that run emulator exlusively, and are EXTREMELY good.
At the same time, there's just something about having an ORIGINAL nes - rather than emulator or a re-creation. Also - the original will have virtually zero input lag, whereas most re-creations have more for a variety of reasons.
Curved screen with the big bulky back - yeah.
(Although CRT can have flat screen also)
It generates an image in a different way than the modern LEDs - has a response time of pretty near zero... as opposed to LED's which have a slight lag in the creation of the screen from an input.
Slow Mo Guys have a really great YouTube video on the differences filmed in extreme slow motion between CRT and LED... and even features SMB1 on an NES
^ animated GIF of CRT generating an image. LED generates FRAME by FRAME, CRT generates pixel by pixel, from left to right
It's also why you can't play duck hunt (or anything with the light gun) on a LED tv... and you can on a CRT
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