1. Silent Storm / Silent Storm Sentinels
A full-3D-realistic-physical-destructible-environments Tactical Game similar to Jagged Alliance. When it was released, it got 90% ratings and yet didn`t sell many copies. Perhaps because of the fact that only the most high-end PCs were capable of running it. Very good story, extremely addictive and intelligent gameplay, horrible voice overs. Voted "Best game noone ever played" by IGN.
Can be grabbed from GOG at ~ 10-15 dollars.
2. Europe 1400 - The Guild
Years before The Sims went medieval, this was the ultimate life simulation set in medieval Europe. But it was also a clever business simulation, a crafting and trading game, a Machiavelli-worthy game of political fights and even simulating rivalities of different dynasties over several generations. One of the best games ever made if you are into medieval politics, craftmenship, business and courting.
The problem was - it was difficult like hell, and the best part of the game, the multiplayer, had a tendency to crash the game and destroy the savegame when doing so. Well-sold in Germany, Austria, even here in the Czech Republic and Poland, still sufficient in Europe, but no chance to be successful all over the world.
3. Into the Dark
As mentioned in the "how do you play horror games thread" - don´t be fooled on that one. It is indie, it is low-budget, comedy, it is parody, it is satirical, it doesn´t take itself serious - and yet it has some very mean horror moments that can scare you to death. Got ratings from 0% to 100% (setting the all-time record on gamer-arena) but is largely unknown because German magazines were afraid to write about the game. If German prosecutors had found one more (yeah, there are some)reference to the 3rd Reich in the game, all printed magazines would have been ordered to be destroyed, and the online magazines would have been at least locked down temporarly. Noone wanted to risk that, even after German courts and the USK cleared the game of all accusations.
Still, if you are open-minded, intelligent and educated enough to get most of the jokes and references, and if you can forgive some bugs, this is one of the best (or at least great & unusual) games of 2012:
A "Trash Game of the Year Edition" including the movie "Night of the living Dead" is sold for 12 Euros at Desura:
http://www.indiedb.com/games/into-the-dark/news/into-the-dark-released-on-desura
4. Several Games by "Cosmos Design" created in the last struggeling years of the c64 for that system.