What games can you recommend that didn't get the appreciation that they deserved?
I've been recently been thinking about Arkane Studio's Prey which is a immersive sim, with a pretty good rogue like dlc, that probably has one of the strongest hooks of any game I've played. If you liked Halflife, System Shock, or Deus Ex it's definitely worth a play.
Are there any titles that might not have been commercially successful that you feel everyone should give a shot?
Uplink - A hacking sim game that's actually quite addictive in a playthrough. Will make you feel like you're in the movie Hackers.
Spycraft: The Great Game - An adventure game that had as consultants CIA director William Colby and KGB Major-General Oleg Kalugin.
I don't know a lot of people that have played these, but they definitely rank up there for me as some of the more interesting and unique games I've played over the decades.
Played Uplink as a kid, later learned about fragmentation for computer memory. Was cool to find out the inventory system wasn’t just a cool game mechanic but was based off how actual memory works.