Pixel art rules - the art of pixel art

Pixel art has always been my adoration; I find it hard to explain, but I think it must be a mix of nostalgia of playing games on Gameboy or Super nintendo and thinking every new game was a master piece. But I also believe that it can be very artistic to manage to represent something correctly having a graphic limitation.
Pixel art certainly had it's beginnings thanks to the limited hardware and display options, the lighter the graphic the easy it is to process in real time. Now a days is hard to see other than portable games or indie developers trying to go down the route of using pixel art as there is practically no need for it. The nintendo 3DS for example, has the capability to render with far better quality than the nintendo 64 could back in its day.
My decision to make my game level 'Sanctuary' using pixel art was merely a personal preference to be able to demonstrate another kind of artwork, get out of my comfort zone and at the same time please my inner child.
Once I got into it, I noticed a massive community online and a huge range of people that focus their work only to pixel art. With this saying, I not only found endless numbers of tutorials, but also a great number of 'rules' that pixel art has; is not as easy as it looks.
Because you have to limit the amount of details (depending on the size of the sprite/character in hand) linework or shading can't just be done with brush strokes, but instead, it has to be carefully placed. It's surprising how easy it is to spot a single pixel out of place, even when is a big pixel art work.
Where a piece of work goes from pixel art to just a low resolution of something bigger, that I don't know, but after my first attempts to make some examples, I think I gained two things: the admirations for everyone who decides to only work on pixel art and the fear that this project might take longer than expected to finish the way I wanted.

Because the rules of pixel art are not 'official', I wont go through them, but I did found this forum, part of the Pixel Joint online community that I found immensely useful, in case anyone wants to give it a go.
There are a lot of examples of games out there that I could mention and elevate to the state of divinity, such as Megaman Zero, Metal Slug, Pokemon, Final Fantasy Tactics Advance, Sword & Sorcery among many many more.
Instead I think I'll mention some artist that I really admire for their unique style and that have been a huge influence while making my own work.

- Syosa:
This artist is like a god to me at the moment. (notice that I'm using some of his work for testing the engine)
Not only his/her pixel art is amazing, but the style and animation is just beautiful and fluid. On his website (only Japanese) he posts and explains a lot of his process which turned out to be really helpful.

-Cocefi:

His/her work is just adorable and with a very lively animation. Isometric views are his speciality, and love the way he makes little diorama-like images full of detail. 

- Johanvinet:

His work is fast, dynamic and very consistent. He is a very active person in different communities and post work all the time.