No Sonic Adventure game?
Invalid list.
Yes, indeed, several high profile Dreamcast games don't appear on my top 20 list:
Sonic Adventure: A good experience, but not great. A big buggy and frustrating in execution, and while it has some strengths, it just struggles in 3D for me. But then again, I liked Big the Cat, and I'm probably the only one who felt that way.
Sonic Adventure 2: Honestly, I've never played this one, and I really ought to. I did play a demo disc of the first stage and thought it was fun, although the issues with controlling Sonic in a 3D environment were still there (and, honestly, will always be there). This character just doesn't translate from 2D to 3D nearly as easily as Mario.
Shenmue: A highly impressive tech demo that predicts the rise of Grand Theft Auto and sandbox videogames, but there's not very much to do. The novelty of opening every drawer and talking to every person wears thin. I also felt the combat was a touch clunky, but this just might be the game's Saturn roots showing. Honestly, this should have been on Saturn. Its impact would have been much greater.
Shenmue 2: Again, I haven't played this one yet. I really would like to play one of these days, I wonder why I never got around to playing this one? I would love to check it out sometime.
Jet Set/Grind Radio: I love this game's techno trip-hop design and art style, it's just amazing for its time. The controls are a mess: your movements are far too floaty in the vertical, yet far too twitchy in the horizontal. This leaves jumping and grinding rather difficult for me, as it lacks that sense of weight and speed that Tony Hawk Pro Skater nails so perfectly. If you can work around this, fantastic. If not, well, sorry.
Virtua Fighter 3 Team Battle: A very solid arcade conversion, almost perfect and better than its reputation. But it does show its age when compared to DoA2 and SoulCalibur, and I also think Fighters Megamix is a better fighting game, a smoother and more fluid experience.
Sega Rally Championship 2: I played this a lot back in 1999 and 2000, as I loved the original on Sega Saturn. The frame rate issues, jogging between 30-60 fps, always felt somewhat jarring, but this might not be as big an issue today. The course designs, however, are not as good as the first game, especially that final city course. I did like the 10-year championship mode, however. Overall, a fun experience but slightly disappointing. But the last time I seriously played was over 20 years ago.
Quake 3 Arena and Unreal Tournament: I played the heck out of Quake 3 on Dreamcast, as it was the best online gaming experience at the time. But the frame rate sucks. There's no getting around that, and now that I'm fully immersed in the high holy Lobotomy Trilogy on Saturn, I just can't enjoy this version of Id's classic. I really do wish Lobotomy were still around to handle this translation, and then give us a DC version of Powerslave. That would have been amazing. Same goes for Unreal Tournament, a series that I loved dearly on PC. A lot of Dreamcast games have silky smooth 60 fps, but many others just struggle with frame rates, and that always irritated me somewhat. That said, I really wish these two franchises would return. Why did they go away?!