You likely know this as Resident Evil - Code: Veronica X, an updated rerelease of RECV with many improvements and extra content. (The PS2/GC ports got western releases, the DC one didn't.)
Use remote-controlled fighter ships to repel the mysterious aliens who are attacking the Mars colony. A horizontal shooter from G.Rev, a team of former Taito arcade devs (all similarities to Metal Black and G-Darius are fully intentional). Features a "border system" instead of lives: each stage has three routes - green, yellow, and red. Dying gets you moved down to a harder route, but scoring well enough lets you move up on the next stage. Great jazzy soundtrack and nice graphics.
Capcom vs. SNK PRO
2D Fighting
Updated version of CvS, better for the following reasons. 1. Every hidden character - Akuma, Evil Ryu, Shin Iori, is unlocked from the start. 2. MOTHERFUCKING JOE HIGASHI AND DAN MOTHERFUCKING HIBIKI. 3. More game modes with new features. 4. New moves for certain characters.
Fun fighting sequel that is Japan-only on Dreamcast but still playable like most fighting games made by Capcom, even without knowing Japanese. Also on XB/PS2/GC. XB/GC versions are the best by standard. A lot of people don't like XB/GC versions because of numerous gameplay changes, the most major one being the removal of roll cancels.
Pretty decent shmup by MileStone, a team of former Compile guys. Simple but functional graphics, and trippy electronic music. Choose one of three fighters, each with different traits, and go shoot the bad aliens from another dimension. But wait! The game has two unusual features. First, you can swap between two parallel realities, the chaos field and the order field. You are more powerful in the chaos field, but the enemies also attack with more intense pattern there. Second, it's a boss rush game. So all you do is fight one huge-ass boss after the other. It's a far deeper game than a first impression could make you think, so check this guide. Also on GC and PS2, and as part of the "Ultimate Shooting Collection" for the Wii.
Port of an arcade that's like a mix of Breakout and Virtua Tennis. Short and sweet.
Fire Pro Wrestling D
Sports
A timing-based grappling engine that takes some actual skill to use, misnamed versions of real wrestlers to avoid copy infringement, and a deep character and AI editor, this game is good even if you don't like wrestling. Seriously. Play it.
Frame Gride
Action
Hardcore mecha arena fighting / third person shooting game with gritty medieval aesthetics by From Software.
Sega Sammy's second installment in the popular Guilty Gear series. Combat is frantic and deeper than pretty much any other 2D fighter out there. Probably the only fighter on the Dreamcast on par with SFIII: Third Strike's gorgeous sprite work.
Ikaruga
Shooter
A spiritual successor to Radiant Silvergun. One of Treasure's most well known games. Involves shifting polarity between black and white to deal huge damage to the opposing element while absorbing bullets of the same color. Much more of a puzzler than a shmup as there is a strict method to its madness. Also on GameCube, XBLA, and PC.
Karous
Shooter
An avian girl is caught in the middle of a war between heaven and earth. The very last official release for the Dreamcast, similar to Milestone's previous shmup Radirgy but with more somber aesthetics. Also on the Wii, as part of the "Ultimate Shooting Collection".
A very artistic and deep game about evolution and helping other creatures to do so. An underrated gem, even considered the best Dreamcast game by some, this is the last in a loose trilogy after PS1 cult classics Moon: Remix RPG Adventure and UFO: A Day in the Life. Created by a team of ex-Squaresoft devs, with music by Academy Award winner Ryuichi Sakamoto.
A girl is isekai'd to a realm between dream and reality, and has to help the locals to retrieve the magical MacGuffin and come back home. A cutesy, colorful, very very girly (made by an all-female team) fairy-tale-like mix of 3D platformer and action RPG.
A badass vertical bullet hell with flying robots. It uses a "buzz" system that rewards playing dangerously: your power increases while you almost touch the enemy's fire. But don't actually touch it because then you'll die. Also on PS2/Xbox.
Puyo Puyo Fever
Puzzle
The final Sega released game on the DC (from 2004!!!) A crazy fun and fast-paced puzzle game with delicious cartoon graphics and upbeat music. JP-only, but with an English option. Also ported to nearly every platform around the time of release.
Puyo Puyo~n
Puzzle
Aka Puyo Puyo 4 (title's a pun in Japanese). The gameplay is similar to PP2, losing the sun puyo from the previous game but adding character skills.
In a world where some people suffer from allergy to radio waves, a schoolgirl has to fight the terrorists that have taken over the pharma company that's trying to find a cure. Humorous cel-shaded vertical cute 'em up, and a very late release for the system.
A kid ordered some pizzas for a party, but the delivery guy shows up with a super combat armor. So he decides to become a hero for hire. Zany action-RPG with a 3D fighting combat system, kinda like Shenmue plus comic books. Remake of a Mega Drive title that also never left Japan.
SEGA's absurdist self-parody in which you play a boy recruited off the street to get the company back in shape before it collapses. First you'll have to insult and compliment the game developers into submission via RPG-style shout-offs, then put them to work developing games under a strict schedule. Lots of Japanese visual gags, SEGA references, jabs at other games and companies and the like.
Shmup that plays like Gunbird 2 in which the people count as the ships. Dialogue heavy- and JP only, but playable. Also on GC/PS2, GC version is JP only as well, while PS2 version (called "Castle Shikigami 2" in US) is in full ENGURISH.
Space Channel 5: Part 2
Rhythm
This is the Japan only Sequel. Same as the first but features Michael Jackson as "SPACE MICHAEL". There is a full English release made from PS2 game version, now replacing X and O buttons from DS controller to match actual buttons on Dreamcast controller (see link to the side). Also available on PS2, Xbox 360, PS3 and PC.
Seriously, Puzzle Fighting, that IS the fucking title. Capcom made a genious idea with this shit and it works out well. Best version of Puzzle Fighter II. Well, maybe the HD remix is better, but I wouldn't know. If you want to acquire this, Capcom Fighter Collection Disc exist online. Matching service version has online versus!
Super Street Fighter II X For Matching Service
2D Fighting
Probably the most complete port of Super Street Fighter II Turbo ever due to its extensive customization options. Japan only and very rare, as it was a mail order release. The HD Remix version later released for the PS3/Xbox 360 was based on this version.
The King Of Fighters (series)
2D Fighting
Even after the Dreamcast was discontinued, it got new KOF releases all the way to 2002. They are basically identical to the Neo Geo (only 2000 had remixed music).
Triggerheart Exelica
Shoot em' up
A flying anime girl robot shmup with a literal twist: other than shooting the enemies, you can also use a tractor beam to capture them, spin them around, and slam them against other enemies. By the same devs of Shienryu. Also on PS2 and XBLA.
Trizeal
Shoot em' up
A damn sweet shooter from a tiny developer, with a very strong old-school feel; challenging and intense, good graphics, nice soundtrack. Also for PS2 (lotsa slowdowns), PC, and part of the Shooting Love 200X compilation for Xbox 360.
A unique shoot 'em up for Dreamcast that can best be described as a 2 player competitive puzzle/shooter. Get chains to put enemies on your opponents screen. CRAZY fun with another player to compete against!
Under Defeat
Shoot em' up
G.Rev’s second and final shmup for Sega's deceased wonderbox. This time its a Vert set in WWII. Awesome graphics and some unusual gameplay: rather than just shoot upwards, you can turn your helicopter to an angle. Widely considered one of the finest Dreamcast shooters. Also on PS3 and Xbox 360. The Limited Edition came with a cool arranged soundtrack CD.
Just when you thought there was no Darkstalkers games on the Dreamcast! Capcom literally had EVERY fighting series on this console alright. Vampire, A.K.A. Darkstalkers, in 2 of their best literations from the JP circuit. Now with online and other shit.
What's Shenmue
Action-adventure
A mini-adventure that served as a demo/preview of then-upcoming Shenmue. Ryo is looking for a Sega higher-up who got in trouble with the local thugs.
A quite rare Japan-only bundle of a book covering Yu Suzuki's remarkable game development career, and a compilation of five of his early arcade hits. All but one were playable in Shenmue 1 and 2, but it's convenient to have them all promptly available on a single disc. Games: Space Harrier, Hang On, After Burner II, Out Run, and Power Drift. If you understand moonrunes, get the book here.
Zero Gunner 2
Shoot em' up
Another helicopter shmup this time from Psikyo. Feature massive bosses all with multiple forms. Bit of a cake walk up until the last stage but still awesome.
