Wow, don't ever do this. Don't ever recommend this to any new programmer - you will put them back so many years if they try do things this way.
But this does bring some nice analogies.
The article IIRC isn't recommending a someone who never coded before to jump in and make tetris. He was suggesting different games to make in order of (in his opinion) complexity. So if you know programming but want to start making games, tetris is a good one to start with because of lack of AI, and so forth.
I see. Well in that case I'd have to say just go straight to Galaga.
The thing is that you are making the game in tiny bits either way. It's not like someone just sits down and codes Galaga from scratch in one try and then hits compile. First you'd just try put an image on the screen, then you move that image, then you add in player controls, then collision, and then finally AI. At every point of that after you've added controls it's a version of one of the other games (and people find it surprisingly fun to play a game that they themselves have made regardless of how pointless or unpolished it is).
The main reason for suggesting any of those games is that they're 2D scrollers which is why they're so easy to make.
You need first year, university maths just to add that extra dimension and that's not even including learning about good collision detection and occlusion - it's just putting a model on the ground. Hell, even adding rotation to a 2D game already means your maths knowledge needs to be decent, but again you can do it in small parts and that will make the progression smoother.
So now that I've explained that, you may ask more specifically. Do you want us to tell you how to learn traditional art before delving into pixel art, or are you already capable of doing traditional art? or do you want us to tell you which kind of perspectives are easiest and what kinds of games to copy to kind of get an idea of how to make generic pixel art (really slowly)?
If you just want the latter I really doubt people here are going to be willing to help, because they take a lot of pride in not only their work, but also their advice.
I'm capable of doing traditional art, and have done some in the past. I'm not what you would call an accomplished artist, but I'm not entirely a beginner. I'm not asking for either of these and apparently, again, I did not communicate what I was asking very well.
Actually to me it sounds like you want the former, which is good.
As an aside don't apologise about wasting time or whatever it is that's happening. People just won't reply if they're actually done helping you and mostly there are gruff, jaded members replying (because of how many people come through and ask questions and then just leave without learning anything and thinking everyone hates them), so if you feel like you're being attacked, or upsetting people - that's perfectly normal.
I'm just putting down stuff that I've learned in the hope you will find useful information in it. It's also good for me to write these things down for my own sake, so it isn't wasted no matter what.
Moving along.
Learning will be different per person, but I will give you an order and some reasons and hopefully you can just take what you can out of it and do what you must. If I still haven't understood you correctly, then you'll just have to wait until someone else does.
(To start off, always draw realism first then move on to cartoony. Also, throughout all these practices never use the eye dropper tool on your reference image because this destroys the purpose of the exercise.)
Draw pictures of realistic faces from photos/real life. Lots of faces. I'm talking 10 faces a day kind of thing. Never erase. Never be ashamed.
As was mentioned your brain can see errors in faces really easily because it's trained to recognise them, so if you want to learn how to copy proportions well faces are your best bet (and then hands, then bodies).
Why mustn't you erase or be ashamed? Simply because your mistakes are an important lesson. For one it shows you how your brain interprets what it sees. Often this results in eyes that are too big (your brain puts heavy stock in eyes) and other deformities because that's what your brain focused on most and so they appear bigger to you (it might not be eyes for you). REMEMBER THIS. Later on you'll be taking advantage of this effect to create your very own style (style for many artists being the slight differences that are created as a result of this cognitive bias). The style will come naturally if you just let your brain do its thing.
So then seemingly entirely contradictory to that we now want to iron out those small imperfections. Actually not iron, more like just going over it with your hand because we don't want it entirely flat (or you'd lose your style and your art would be boring). This will come naturally once you see your mistakes and begin fixing them. Eventually you will be drawing realistic looking faces and they will have a special something you've added unknowingly.
You will need to learn values to shade realistically and give things depth. Depth is especially important in pixel art because it is a 2D medium, so all depth has to come from correct representation of light.
To learn value you do value studies. Simply take a picture and greyscale it and then try to copy it as accurately as possible (again take a picture of something real: bodies, faces, landscapes with nice mountains/hills - something with a nice amount of large, easy to identify shapes).
Don't spend long on each picture and zoom out/blur your eyes so that you get the overall shading correct and don't get bogged down by details.
Now compare it to your reference image. You'll notice the same sort of imperfections as with sketching faces. These are your style. Flatten them out a bit, and unlike the sketching when it comes to value you can actually iron them out entirely if you want.
Now that we have those down, let's work on colours. You can go straight into pixel art to learn colours if you like.
Again just pixel something from real life. Take a picture and scale it down to some tiny size (128x128 or something) and have the full version open next to you, and then try to create the image that is as small as the 128 version, but with as much detail as the full image (obviously this is impossible, but you are trying to learn how to represent things at this point more than copy them exactly).
You'll use the smaller image to gauge what colours to use more or less. You could also rather to thumbnail studies to get colour right and then go into this pixelling of scenes, which ever works better for you.
Alright now you are the master of copying realistic images of all types! Well done.
NOW comes the part where you can bring back those imperfections. You don't HAVE to look at any other artists's work, but you can if you want.
Your brain was giving you hints at how it recognises things with those imperfections earlier, so let's just use those to make our images unique and recognisable. Easy!
Draw cartoon faces and shade in a cartoonly manner (one colour for where light hits and one for shadow, or something like that). You will find this easy because your brain was already doing it and now you have mad skills.
Any medium is fine for this, but rather don't use pixel art just yet.
Finally, you are now the jedi-wizard master of representing real life things with believable less-real things.
Just yolo straight on in to any pixel art project. Anything you have been drawing you will be able to pixel and if you want to pixel something you don't know how to draw, learn to draw it first.
Once you've drawn something a bunch of times you will be able to pixel it with such ease that you'll wonder why you ever thought pixel art was difficult.
Further you will need to hone your skills.
Redo cluster studies because this time you will understand why they are so valuable.
Experiment. Never be happy with your current level of skill or you will stagnate. Try new things.
And that's about as much information as I can give with regards to what order to try doing anything. If you're already able to do any of those parts then just do the others, maybe redo a few things in case you've picked up bad habits.