Sonic Jam may not be good for spreading on toast, but is great fun to play.
Story - since this is a compilation, and the fact that these are the old sonic games, the story isnt really applicable, Robotnic is after the Chaos emeralds and its Sonic's job to stop him.End of story.
Gameplay- the basic premise of the Sonic games have been discussed many times before, so its better to concentrate on whats different in Sonic Jam.
in terms of gameplay, Sonic Jam is better then the originals for a number of reasons. Sonic has been given the ability to perform a spin dash in Sonic 1, which he wasnt able to do in the original (or in pretty much any compilation), this actually makes the game more fun then it was before, and levels the playing field against the other sonic games. Also, another noticable thing is that all 4 sonic games seem to run faster and more smoothly on the Saturn. While the old Mega Drive versions were blazing fast, there were times of slowdown when things got hectic. Sonic team has taken the time to adapt the games tro utilize the far more powerful Saturn and the result are smoother, faster and better playing games. many compilations even on the modern consoles, are not adapted and thus the slowdown remains in them.
even better, there are new modes to play the new games. You can choose "Original" and "Normal". Original are identical to the mega drive versions, while Normal are actually remixed versions which make the game a little bit easier, due to a somewhat different level design.
overall, Sonic Jam makes the sonic games more fun to play.
Graphics and Sound - As far as the Graphics go, there are minor changes to the games. All the games look essentially the same, but everything seems clearer , it seems as though the resolutions of the games have been increased, as everything looks much sharper, even the colours are more noticable and more vibrant then the mega drive originals. Wether it is due to any additional programming by Sonic Team , or simply the Saturn's higher quality video output , the visuals are slightly improved over the originals. Sound effects and music recieved a similar treatment, as the music is clearer and sounds better then the mega drive versions. Some sound effects have been replaced with new ones completly and overall, the Sonic games truly shine on the Saturn.
Sonic World - Sonic World is the other feature of Sonic Jam and should be reviewed indepedently. Sonic World is essentially a fully 3D sonic stage which acts as a museum where you can view sonic commercials and short CGIs, listen to the music from the games, etc. The Graphics are very good in Sonic World for the time, and have a similar cartoony style that is found in games like Mario 64 and Crash Bandicoot. the control is also very good. Sonic World provides a glimpse to what the 3D sonic game for the Saturn could and should have been like.
In conclusion, Sonic Jam is quite possibly the best Sonic compilation ever made, while it is a slight disappointment that other classics like Sonic CD were not included, there is more then enough here to satisfy anyone looking for a superb platformer. the visual and audio upgrades, the new modes of play and the features found in Sonic world, make Sonic Jam a worthy purchase.
on top of that Sonic Jam is quite affordable today and is one of the cheaper Saturn games, so this is excellent value for money.