In the original Sonic Adventure, Speed Highway was one of levels that showcased the graphical capabilities of the Dreamcast to the fullest. When playing this level, you could feel that every little detail in it was designed to be a visual spectacle – much like in the rest of the game, but this particular level just pushed the hardware to the very limit. It was gorgeous to look at, with all the crazy lights, the roads going upside down, with helicopters and the police chasing after you. The scene with Sonic running down the side of a building is one of the most memorable moments in the entire game.
The SADX version of the level has a significant number of changes, some arguably conflicting with the “intended” atmosphere from the original Dreamcast version. From the start you can see how the lighting sets a completely different tone for the stage, making it darker and eerie green. The PC version’s lighting is almost non-existent:
The buildings are only correct on the Dreamcast because the windows are lit up. On the Gamecube/PC they lack such lights. This could be considered an oversight, as it would’ve been simple to make the windows brighter – it’s a single material flag:
The breakable glass has almost completely lost its environment mapping effect, as well as its unique texture. It is now using a green texture similar to the rest of glass surfaces elsewhere in SADX:
In all versions except the Dreamcast original there is a bug with the red transporter. Its model has a material flag that enables transparency where it isn’t needed, making parts of level geometry visible through it. It’s especially noticeable in motion.
The grabber basket that brings Sonic to the upper level has lost its shiny surface (environment mapping) and is now properly textured instead.
The helicopter went through a similar transformation, only retaining the shiny effect on its windows:
Here’s another example of this change from Act 3: the cars are no longer shiny and use the same green glass texture as many other areas in SADX:
The Dreamcast models use a low-resolution texture and distort it to get a “metallic” looking surface. This effect is used by many models in SA1 and SADX – the lion in Casinopolis, icicles (SA1 only), window reflections in Station Square, cars (full models in SA1, windows only in SADX) etc. The Dreamcast version certainly relied a lot on this effect.
The removal of environment mapping in this particular case is both a good and a bad change: although the textures allow for more detail, the “metallic” effect is gone.
Speed Highway has several objects with blinking lights, which are seen more often in Tails’ level. This radar/satellite dish tower has a glowing light at the top, for example. In SADX its light was disabled.
Another missing effect is the rotating lights inside the bottom part of this type of platform in Tails’ stage:
The lights are still there, but you can’t see them because SADX is struggling with transparency.
The lights on Eggman’s missile were not removed, but for some reason their blinking is broken in the PC version:
If you look closely, you can see that the smoke effect looks lower resolution in the PC version. This is caused by alpha rejection, more on that in the Transparency section.
Texture quality suffers again, especially in the PC version, where some textures are half of their original resolution in addition to having been recompressed multiple times:
Act 2 has also lost a lot of ambience: the red fog near the bottom is gone, and the updated glass texture doesn’t seem to fit the level’s theme:
The intended colorful ambience of the original level is darker and washed out in the ports:
Strangely, at the end of Act 2, there are no rings to collect using the magnetic shield that you get slightly earlier.
The buildings in Act 3 had two effects in the Dreamcast version: you could see the skybox and parts of the level through the windows because they were semi-transparent (so it looked like a reflection), and the texture on the windows themselves had environment mapping:
Gamecube (PC footage shown)
The SADX version of the level has no such effects. Although the all versions of the game still support environment mapping, all windows in this stage use a static opaque green texture that never changes regardless of where the camera is.
Act 3 in general appears to have lost a lot of its original atmosphere. Here’s a comparison of the starting point as Knuckles. The Dreamcast version sets a different tone for this level. The PC version, apart from washing out the already simplified Gamecube lighting, adds fog that washes out the atmosphere even more:
If you walk around the stage a little bit, you’ll notice that the advertisement boards on the roof look strange in SADX. The model is rendered in an incorrect order:
Since the PC version processes material colors even when it’s not necessary, the broken container bottoms have a green tint.
The fountain uses a different model in SADX, seemingly done to mask issues with self-blending objects and transparency order.
The Dreamcast version had dynamic fog in this level, which got thicker in some areas (possibly to improve framerate), but subdued in other areas to improve visibility. Even when the fog got thicker, the areas close to the player were not obscured by it. The Gamecube version gets rid of the fog altogether, while the PC version brings it back, but fog distance is never adjusted on PC, which makes it wash out the colors:
Here’s an area where the fog goes away on the Dreamcast. As you can see, the colors in the level are constantly washed out in the PC version because the distance where fog begins is much closer to the player:
The Master Emerald pieces have lost their shading in SADX and look a lot brighter and less transparent overall. This could’ve been possibly done to let the player see them from further away.
*Not a video but you can still see it still doesn’t have proper shading.
Speed Highway is one of the most severely changed levels in SADX. While it is completely subjective on whether which version is better, it is factual that some of the changes, notably the green lighting in Act 1, both conflict and do not compliment the original atmosphere as originally intended.
With Lantern Engine you can enjoy this level again with original lighting, and with Dreamcast Conversion you can have this level reverted to the original version with all transparency effects restored, as well as tweaked fog for better visuals. Check out the “Fixing the PC version of SADX” to find out how to install these mods.