Yeah it's true....Invader basis main body of work on a space invader game....let's take it up a notch and say graffiti as in writing your name. It could be consider a brand. By repeating your name on trains and buildings or benches you could say you are advertising.  If we continue extrapolating one could argue that Obey, Banksy, Kaws, Hirst, all have an identity and none of it is truly a new idea. Mad innit!

In Strasbourg where I live there is a real copycat of Invader ( better artworks in real anyway, even if the Storks are not my cup of tee.

Does Invader knowing him or that ? What could he do anyway : he fixed hundreds of these around  the town !
He is an Invader fan too …

instagram.com/stork_pixelart?igshid=MzRlODBiNWFlZA==

http://instagram.com/p/Cisd3qJqe3U

Stork is a dork… Those are lame.

From Invaders site

Haha comment of the day... 'Dork' is criminally underused.. 

When talking about derivative, we strictly talk about an artwork.   Here, the goods are totally different, they are enamels pins produced in bulk quantity and fall under the term "merchandising".   

Is this direct competition to artist's market?
Take Bansksy's case as a reference, considering that Invader has a shop and does sell merchandising of his images, then by selling enamel pins (even for charitable purpose) and map (Invader's main product) is considered by law as direct competition in a similar market.   

Is their IP violation?
---To Invader - Considering design of pins are copy&paste of design done by Invader, yes there is. If you had done your own design, different story (see below).  What about the map? Well, you can print maps and put location tag in it, no issue here... just be wary with name you give, it is possible that terms like "Invader map" are Trademarked, so beware with names you use.  Considering Invader's communication above, they do see this as IP violation and it is indeed; don't forget copyright covers the artistic expression/concept... but for Invader, it is murky as he is himself doing unique/exclusive art and products using already copyrighted material.  To cut it short, Invader can protect his "expression" (his artwork or art/image) but not the "idea" nor the "concept", as taking an almost domain-free or overused image (Space Invaders) in mosaic style can't be protected by IP law (just like you can't protect a chord progression in music or facts or codes/formulas)
--To Square Enix - Square Enix has full right on Space Invaders but they don't enforce it much, especially for small producers, distributors, merchandisers, etc.  but they can decide to enforce it anytime.  So selling a small bulk of enamel pins having Space Invaders on it should be fine.  This said, you can write to them, they may accept if project is small as yours - www.square-enix-games.com/en_GB/documents/licensing

Drop the map!   Stick to enamel pins but do your own design, make sure that keywords and words used as changed to avoid any Trademark issue.  If you do your own image, no problem. If you get Square-enix authorisation, the better.     Invader is a bit harsh here, but it is what it is.  Moral of the story, do like him, use Space Invaders and make your own design and avoid any terms that may underline you are doing a deceiving direction competition in his market  (note - deceiving, meaning you use Invader's name or brand text to deceive clients in same market); as long as you keep it clean (clearly distinct your work from Invader), you will be fine.

Many people known Invader's real name, he can be find online in 5mn as there are many old magazine interviews mentioning his name, that's when he used to sell his "porn" (Canal+ type) mosaic at Les Puces (Paris).  Even getting his address and his parents address online is pretty simple