Great responses in this thread, I always use these if I want to go hunting for some retro games for slightly older systems.
That said, huge chunks of the Dreamcast library. While many of them were made available for bigger audiences later on with re-releases (eliminating, say, Crazy Taxi or Phantasy Star Online because of new-found success), a lot of games still remain rather obscure.
- Shenmue 1&2
Now while part 2 was available for the first Xbox, the whole current available saga still remains playable on Dreamcast only. While aspects of it haven't aged that well, overall it is still an unique journey and still no other openworld game achieved the same kind of calm gameplay pace (going well with the topic of "martial arts learning") and sense of world building IMO. I just hope Shenmue 3 can recapture that essence
Why I think more people should play this:
While a huge amount of open world games followed the footsteps of Grand Theft Auto (and Morrowind), this is also a viable alternative on a less walked path. Also, this is where on consoles, this kind of modern-city exploration/story telling game kicked off; it remains historically relevant to the medium.
- Skies of Arcadia
Available on Gamecube as 'Legends', this JRPG from the mind of Phantasy Star creator Rieko Kodama can proudly stand next to Grandia 1/2, Final Fantasy 9 and similiar then-available classic JRPG-experiences. The amazing world to travel, the airship-battles, the well-realized airpirate theme and amazing cast of characters make this a stand-out RPG.
Why I think more people should play this:
When it was still fairly new, I thought "This is better than Final Fantasy X and Grandia 2... why is noone playing it?". Could finally use a rerelease :/
- Space Channel 5 1&2
Charming retro-futuristic rhythm game with amazing music and lots of humour. And space Michael Jackson.
Why I think more people should play this:
Simple - it's fun, simple, catchy, positive and part of the Dreamcast-legacy of having kinda experimental "out of the box" games available.
- Crazy Taxi 2 (and 3 on Xbox)
Hey Hey Hey, it's more Crazy Taxi. While the first one remains the iconic entry of the series, right time right place, Crazy Taxi 2 introduced a even more frentic customer-system (you could now take on several customers at one time) and went from "kinda San Fransisco" to "this might be New York". While the city itself was more flat, you could now jump through other means and explore the city quite differently. Crazy Taxi 3 went on to "pretend Las Vegas" and threw in the main maps from 1&2 remade for the technical progress of the Xbox as a bonus.
Why I think more people should play this:
There's something about the concept of Crazy Taxi as an Arcade game to kill 5-20 minutes and just rock out driving recklessly to the soundtrack of Bad Religion and Offspring. Again, it's pure fun and 2&3 are different enough from 1 to not just seem as "more of the same", mostly because the cities are drastically different from the first game (though that was also a main argument against the sequels... they take time to grow on you, I admit that).
- Headhunter
No, this is not the Metal Gear killer SEGA probably wished it to be. Still, Headhunter is a clever third person action game with a campy-dramatic storyline. It offers the player several options to solve the situations (sneaky or Rambo), has a top-notch OST and is historically interesting since it already includes early elements of gameplay found in later TPS games.
Why I think more people should play this:
It's still fun to play even with akward motorcycle segments and outdated controls. As an inbetween-step between the mostly more static 3rd person action adventures of the PS1 era and what was to come during the following years, it feels quite interesting with some of the ideas it throws at the wall.
- Illbleed
As a horror movie fan, I learned to love both the more high-production value shockers as well as the B-movie approach which often would replace subtle horror and deep storylines with cheap but surprising scares and creative usage of "sex & violence". Illbleed is this for videogames. As a visitor to your fathers horror theme park, you and your group of friends follow "mini stories" in different attractions which spoof well-known horror clichés. You can actually die from fear, so you need to preemptively find traps and scares. Yeah, the game is somewhat offensive and difficult to control, but it's IMO a hidden gem of the Dreamcast library for its unique take on the horror genre and ... yeah, its "surprising scares and creative usage of sex & violence".
Why I think more people should play this:
This is no Resident Evil or Silent Hill. It's a playable grindhouse cinema movie with lots of ideas I wish would've influenced other horror-games as well.
- Rival Schools 2
Capcoms rather unknown fighter is mostly notable for humour, air combos and a really colourful cast. Set in a typical shonen manga "martial arts schools fight each other" setting, I can't think of another game in which you can beat up a teacher as the member of the school swimming club while 'swimming' through the air or beating the s*** out of a tennis player with a violin.
Why I think more people should play this:
This game released around the time Capcom, IMO, had its peak of creativity regarding fighting games. This shows: A more crazy yet likeable and diversive cast was never again featured in a Capcom fighting game.
- REZ
This will probably find a lot of new fans through VR. It's a game that combines in a way music gaming with a rail shooter, being superb both in style and gameplay. Seeing this wireframe world coming more and more to life while every shot is visualized and audible as a beat is still an amazing way to zone out.
Why I think more people should play this:
I believe REZ hasn't aged a day since its initial release. I know I overuse the word "unique" in this post, but REZ is and it was ahead of its time in a lot of ways. Simple gameplay, but deep experience.
also worth noting, but I am running out of time now:
- Jet Set Radio
- Daytona USA 2001
- Under Defeat
- Powerstone
- Bangai-O
- Gunbird 2
Dreamcast also has the, in my opinion, best version of
Dino Crisis 1.