OK, so the main character is compromised of green balls, don't let that make you overlook one of the better 'run and gun' games to hit the Megadrive / Genesis. The shallow premise for the game is that humans have ruined the planet Earth and left the subsequent tidy-up job to their robots. You assume the role of the titular Vectorman, who has to contend with the rather unfortunately fact that all the other robots have turned evil and must be stopped before the make the Earth an even bigger mess than it already is.
The gameplay is quite similar to other 'run and gun' games, like Gunstar Heroes for instance. One nice feature is Vectorman's ability to do a super jump with the aid of his booster rockets, which gives players a bit more lift to get to harder to reach platforms. You can also perform a rather neat airborne attack. There are many interesting power ups including morphing into temporary vehicles, bombs, and amphibious vehicles of sorts to complete your objectives.
Although it's a little grey in places, visually this game pushed the Megadrive to its limits. The camera and scrolling direction switch at certain points and this creates a brilliant sense of depth. You could easily be persuaded that this was a Playstation 1 game, such is the speed of the on-screen action. The multi-limbed sprites move extremely smoothly and look fantastic. The pyrotechnics are handled really well and some of the end-of-level bosses are truly outstanding.
In terms of depth, there's lots of hidden areas so once completed there is always more to come back for, making it decent value for money. However, when compared to the likes of Contra III and Gunstar Heroes (which are champions in this genre) I feel Vectorman on the whole just falls short. It doesn't really add anything new but is still great fun to play all the same. If you've already purchased the aforementioned titles, then this should be high on your shopping list.