I've had this for about two or three years, generally I've put this on the garbage side of things, trying to half-heartedly sell it here and there. What is it, well a labeless version of Spelunker on Famicom, lol. Check out the pics please:
(https://obrazki.elektroda.pl/6372132300_1610906732_thumb.jpg) (https://obrazki.elektroda.pl/6372132300_1610906732.jpg) (https://obrazki.elektroda.pl/7403810700_1610906748_thumb.jpg) (https://obrazki.elektroda.pl/7403810700_1610906748.jpg) (https://obrazki.elektroda.pl/3591205800_1610906767_thumb.jpg) (https://obrazki.elektroda.pl/3591205800_1610906767.jpg) (https://obrazki.elektroda.pl/8893324600_1610906786_thumb.jpg) (https://obrazki.elektroda.pl/8893324600_1610906786.jpg) (https://obrazki.elektroda.pl/7195384800_1610906798_thumb.jpg) (https://obrazki.elektroda.pl/7195384800_1610906798.jpg) (https://obrazki.elektroda.pl/3788667000_1610906809_thumb.jpg) (https://obrazki.elektroda.pl/3788667000_1610906809.jpg) (https://obrazki.elektroda.pl/5385735300_1610906824_thumb.jpg) (https://obrazki.elektroda.pl/5385735300_1610906824.jpg)
The stickers on the back were added by me, and the black thing is covering a shop label, no need to give away my sources, sorry :P
Tonight I was about ready to chuck this into a set of stuff that I'm trying to move, and something dawned on me, Spelunker was only a led game, right? And this one has no led.
Later I decided to look it up on bootgod, totally different PCB/chips being shown for Spelunker.
http://bootgod.dyndns.org:7777/profile.php?id=2258
As can be seen from my pics though, it definitely seems to be a legit irem PCB ...
Thoughts on what exactly this is? Something special, or just garbage?
Let's discuss.
It's legit:
http://bootgod.dyndns.org:7777/pcb.php?PcbID=548
You should dump it and see if there are any differences.
Edit: the one you linked uses rom for chr and prg, while your cart uses chr ram, so definitely there's a difference. Maybe a proto?
No Famicom game will ever be garbage. Good luck with the pursuit.
Spelunker wasn't only an LED game, they released two versions of it, one with LED and one without. The ones without LEDs are a lot rarer. Basically late in the game's release they realized the kids weren't that into the LEDs and they made production of the cards expensive so they ditched them.
I did a post about them a few years ago on my blog, they did the same with Sqoon, 10 Yard Fight and Zippy Race:
https://famicomblog.blogspot.com/2013/11/my-new-sqoon-missing-those-lovely-irem.html