This definitely has to be the best of the officially released horizontally scrolling shmups on Dreamcast, and by no small margin. Each level here has three slightly different versions (or borders), and every time you die you get booted down to a lower version of the level, drop off the bottom border and the game is over. As standard you get given a rapid fire shot (hold the button down) or a slower homing shot (press button) and its wise to swap between both moves regularly, outside of that you get the usual power-ups and some intense boss fights.

Precise, sim-ish racer from Melbourne House that's packed full of attention to detail (you can even do the full 24hour race in real-time!). Le Mans is a well crafted game with some of the best graphics on the Dreamcast, with clean visuals and excellent reflection effects and filtering (reportedly being the only game to use the hardware's Anisotropic Filtering). A later PS2 port was also made but had a few graphical downgrades so if you have both systems go for the Dreamcast.

Feature-rich 2D fighter from Capcom that has their main characters taking on those of rival fighting company SNK. The main gameplay inclusion here is the ability to choose from a large variety of "Grooves", you get different abilities depending on which groove you choose, so with one Groove you may be allowed to block in mid-air for instance, but not parry, whilst a different Groove will give you custom combos or a different type of Super. The game is one of the more impressive looking fighters on Dreamcast due to incorporating 3D backgrounds, and is pretty much arcade perfect due to the Dreamcast sharing hardware with the original arcade machine the game was from. Out of the ports the PS2 version is also very good, but less so the later GameCube and XBox versions.

Quirky rhythm action game where you try to keep in time with the onscreen prompts. The game has you playing a space reporter Ooh La La as she tries to save the station from aliens by taking part in a dance-off!

An excellent first person shooter ported from the PC, and yet another excellent reason to invest in the Dreamcast's mouse and keyboard peripherals. The game is a very well balanced multiplayer deathmatch focused title, and its easy to see why it became so big on the PC. You get a lot of quirky weapons here, each with their own tricks and tactics, and a lot of balanced stage layouts (the Dreamcast port especially has stacks of maps). The online component of the game unfortunately no longer functions, but there's a good 4-player split-screen mode available and whilst some stages have lower-ish frame rates there are just so many stages that do run well (Damnation, Loathing, Paladin, Flux, Depot, Sector 9, Core etc, etc), that you're never short of smooth levels to choose from.

Classic lightgun game that's a stalwart in arcade parlours the world over. Basically a town is overrun with zombies and its your job to clean up the place. The gameplay is the usual light-gun fare, the Zombies lumber towards you while you desperately try to put them down with a headshot, civilians with death-wishes jump out in front of you at inopportune moments and spout mildly risque-sounding Engrish, and the bosses are big and exciting to battle. Definitely one of the most important and popular Lightgun games out there, and the Dreamcast port has some nice extras too.

Dash around the environments shooting off volleys of shots, taking cover and charging into hand to hand melee's in this 2-player Mech combat "Vs" game from Sega. Its a complex, intense game that's best played with the elaborate "Twin Stick's" controller it was designed for, but can be played reasonably well on a pad. Supports split-screen and Link-Up

Large and imaginative platforming and shooting game from Bizarre Creations (Project Gotham Racing, Geometry Wars, the Club) that's in the vein of Rareware's N64 titles like Conker's Bad Fur Day and Jet Force Gemini. The game has you exploring the large environments searching for kidnapped babies. You get multiple different characters with different abilities and have to swap between them during the levels to progress (babies can also only be rescued by characters of the same species). Its just generally a smart, funny game that gives you lots to do and see. A later PS2 port is also available that had some added novelties (the most notable of which was voice acting), but was downgraded in pretty much all other areas (notably texturing, resolution, load times, controls, and draw distance), so I'd say its probably best to stick to the Dreamcast version.

It was a long time coming but when Street Fighter III finally did turn up it did it with style and panache. The main addition here over the earlier games is a system of parrying which allows you to take no damage if you push forwards at the moment an attack connects (as opposed to just blocking which still causes you some damage). The art design here is phenomenal, with the game being full of great backgrounds and fitting music. The Dreamcast actually had all three of the major iterations of the game released on it, with "Double Impact" including the first two versions, and "Third Strike" getting a standalone release. Third Strike is the more popular version, but Double Impact has its own look and feel and is very well ported so its also worth checking out. Final note, the DC version of Third Strike is based on a later, less popular revision of the Arcade machine that is rarely played in tournaments, so if you're looking to go out and play the game competitively you may be better off with one of the other ports.

Whilst Sonic Adventure is probably one of the more dated of the games on the list (hence placing just outside the top 20), this launch title remains a very fun (though occasionally troublesome) experience full of hefty amounts of ideas, and some very imaginative level designs. The game gives you an overworld to explore, the platforming is dynamic and exciting and there's even a variety of different characters to use. The sheer scale and spectacle of this game running back in 1999 cannot be understated, it was mindblowing, there was nothing quite like it out there with this level of speed and exuberance.