I realized (many times) that I opened a blog with a clear hint that it would be about NEC consoles & games, but as you’ve noticed there isn’t anything about NEC, at all, yet…
Promotional games or sample along with alphas and betas are a nice complement to any game collection. They are quite easy to find for current gen (although I have yet to see one for the Wii) on eBay along with last gen and 32/64 bit era, but anything older than that is quite tough to find, not impossible though 😉
Even though PC Engine samples were given away to retailers to demonstrate upcoming games, they do sell for quite a bit on eBay or Yahoo Japan and they don’t seem to devaluate much. The PC Engine had quite a lot of samples produced during its lifespan, but the exact number of titles is not yet known. The PC-FX seemed to have had a good run of samples too and they do pop up on a regular basis.
At the moment I only have 5 samples for the PC Engine, most of them are actually Arcade Card port of NeoGeo titles, here they are.
Ryūko no Ken – Arcade Card (Art of Fighting)
World Heroes 2 – Arcade Card
Garou Densetsu 2 – Arcade Card (Fatal Fury2)
Kaze No Densetsu Xanadu – Super CDrom² (Legend of Xanadu)
Mad Stalker – Arcade Card
On a last note some of the samples bear some differences from the final release, Mad Stalker for example has some different GFX and missing features over the final release. Insert Credit has done an article on the differences that exist between versions of Mad Stalker that I encourage you to read, it features the very same sample pictured above. Although they label it as prototype/sample, it is most definitely the same as above.
Nekofan which is a great French PC Engine review site has done a review in French of the Sample of Gradius 2 for the PC Engine, a great article to read too if you understand French indeed with lots of insight on the subject of samples.
Any questions, let me know