Not a thread to explain why a game that didn't sell was actually good, example, "ICO WAS AN AMAZING GAME!" but a thread to tell why you thought a game that sort of got shit on upon it's release actually wasn't that bad.
My first pic...
Secret of Evermore for the SNES.
Evermore wasn't some huge bomb in sales, but it got tons of flack and isn't looked on fondly, largely because it played like Secret of Mana but wasn't Secret of Mana 3. See, at the time it came out, FF7 hadn't come out yet, so JRPGs hadn't really boomed, they had a lot of fans outside Japan, but it wasn't huge.
So out comes this Secret of Manaish game made by an american division of Square, and people were horribly upset that it was, in fact, not Secret of Mana 3.
But what it did do, was have a fun combat system, different magic system, lots of different weapons to use, that didn't all work the same way, and hugely varying locations and characters to interact with as the story went on.
Also, it's story of sci fi time travel/alternate worlds mixed with 1950s geewhizneez was a quite a change up from the norm of action rpgs at the time.