Sonic Adventure is a single-player 3D action-platforming game from 10 years ago, and is the first 3D main Sonic game in franchise, not including spin-offs. (Sonic R!) As a result of such major step, it changed Sonic franchise somewhat, from gameplay to style and world. You take control of 6 characters with varying gameplay styles to them, from simply beating the level to, gasp, fishing. It also includes a virtual pet thing (A-Life!) in form of Chao.
Now, since this is old game and most people are familiar with it, let's talk about this Steam port.
First, ports history. First came Sonic Adventure, which was a launch title for a Dreamcast. After few years later GameCube players got to enjoy Sonic Adventure: Directors Cut (SADX) which enchanced the game and added missions mode along with unlockable ports of 8-bit Sonic titles. It was then ported to the PC in 2003 year with almost no change. Now, in the 2010 it got rereleased to Xbox 360 and PS3 downlodable services and later it came to PC once agian, onto Steam, as part of Dreamcast Collection. So, how does 2010 Steam version compares?
Xbox 360 and PS3 release actually worked like original Sonic Adventure (Didn't check if that was like split DX or actual original, sorry), with DLC available that would upgrade it up to DX edition, lacking 8-bit sonic unlockables though. For Steam version, it's already build-in into the game, so once you purchase this game, you get your whole 2010 DX edition. BUT the achievements stayed exclusive to console versions only. Also, analog control seems to be translated to digital controls just fine, though there are one or so spots where you will have to adjuct camera around and crawl slowly so not to fall off.
Main competention there comes with comparison to older 2003 PC edition. From technical standoint, the new game release should work better with new hardware, even though I must say that both of them seemed to work fine on Windows 8. I can't notice it myself, but I read that 2010 port has it running at 60 FPS compared to 2003 one 50 FPS. In Steam edition they tried to keep aspect ratio true to how it looked on Dreamcast/GameCube, and as a you will see it being played in a window that doesn't take up your whole (wide) screen, with remaining parts of it being covered with blue-purple pattern... I think that I like staying true to original, with pattern of frame not trying to catch your eyes with colorful art or anything. If you want game to take up whole widescreen by stretching, go with 2003.
Steam release also has this glitch, due to which your configuration simply will not be saved! To make it save, you will have to go and manually mess with your computer's registry (you can read more in Steam forum of the game). I can guess that Steam doesn't allow games to mess with user's computer registry, since I read that retail copies work just fine. Why does it even need registry to work? ...Well, I can guess that it was mostly based off 2003 PC port, from back when most console ports were weird and had no idea how gaming works on computers.
A little thing, Steam SA has only Player 1 controls working... No, Sonic Adventure is not exactly 2-Player game, but there was little bonus that the second player could control Tails on screen, at Sonic's gameplay. Can't do it anymore.
Even though it's based off older PC port, structure of files seemed to change, meaning that programs that worked for 2003 edition, as well as any mods, will not work on this one.
Oh, and finally, in-game changes compared to older title... Well, it's actually pretty much same. Almost. For there is rather big change - all of unlockable Game Gear Sonic games got cut. Yep, that means that the only reason to collect emblems now is Metal Sonic skin that you get for all of them. If you already played 8-bit Sonic titles or actually own real things, then you may not care about this, but otherwise it heavily points at 2003 version as a better one. Why have they done this, I don't know, since you there are no 8-bit Sonics on Steam on sale. Well, maybe only in some kind of collection on XBox 360 and PS3.
Oh, and Chao. Should be same, but I heard that 2010 version changed something about breeding, that not every color combination is possible. Sure thing transferring chao is not supported in PC versions either. And I don't know how it was on 2003, but very often you will experience polygon flickering in Chao Gardens, biggest offender to me being a wearable Golden Pot object.
Allright, that's all for differences. Now, game by itself...
As a launch game for Dreamcast and it was the first major 3D game of Sonic... That alone meant two things: how rushed it will be and how possibly it may change the face of Sonic (not literally, even if some fans are complaining about green eyes). Now, it did had a lot of changes in a way it worked. Most importanly, physics were simplicifed compared to 2D masterpieces, and as a result it mostly became a game about usual platforming and speed. Loop-de-loops used something what some say as "scripted", in that Sonic is "glued" to invinsible path. (And glued badly!). Hell, if in older 2D titles curling onto ball on top of them would give you a speed boost, in 3D Sonic games it tend to slow you down, with possiblity of falling through. Thankfully, the platforming was solid and still allows it to view as a great game, with varied and fun levels design.
By the way, this time around game refused to follow the classic arcade system. Instead it has you going "adventuring!" on the open adventures zones, doing some small stuff to open the entrance to action zones. The adventure zones lets you beat action zones that were already done, and you are able to listen to NPCs lines, which aren't mandatory, but some may enjoy how the life of few people go over the course of the game. You find upgrades there too, some are mandatory, others are not. Action zone themselves are made of only single level and has you accomplishing goals that depend on what character you are currently playing as. Dissapointly, there are only few bosses and they are spread over the game unevenly.
Here is the list of character you get to play as:
-Sonic The Hedgehog. Fastest one, his goal is simply to get to the end of the level. Able to spindash to roll fast and do homing attack at the enemies.
-Tails Miles Brower (cutest fox around). His goal is to get to the end of level faster than Sonic. Able to fly for short time by spinning two tails.
-Knuckles the Echidna. His goal is to find 3 emerald pieces mostly using his sense and occasional hint. Able to glide and attack with his knuckles.
-Amy Rose. Her goal is to grab balloon at the end of level, avoiding a (pathetic) understroyable robot that chases her. Can do hammer jump and hammer attack. Somewhat clunky, it even feels that she can run faster by moving diagonally.
-Big The Cat. Slowest one around (best ladder climber btw), his goal is to catch Froggy... Not with gloved hands, no. With his fishing skills. Most random gameplay style in whole game, and getting A-Rank on trials is a living hell.
-E-102 Gamma. His goal is to make it to the end of level under time pressure. Able to shoot multiple targets, that gives him bonus time.
You are going to travel through as many as overall 11 of varied and fun levels, from beaches and casino to ancient temples and assault on flying ship-fortress "Egg Carrier". I must say that each character has his own set of levels out of all 11, and most often they have their own exclusive parts in action zones. And each of zones come with their own varied music tracks, which make use of good amount of styles, momerable and are joy to listen, as always.
The game was horribly rushed as well. I must say that even a casual gamer would fall through the floor at least once. Comes with unfriendly camera, that hates it when you do something that developers don't want you to (tip: to explore levels)
Damn I ran out of space for review