A fantastic, high-octane, blast from the past, combination demolition-derby/racing game that will sate your need for fast-paced action racers and local multiplayer. 
The fantastic Mashed lacks much in the way of plot, set-up or subtlety at all, but it proves that such things are wholly unnecessarily for a racing game that is this much fun and whimsically cathartic – the premise is simple; as any one of six colour-coded vehicles, outlast a number of opponents while navigating richly detailed maps at top speed and armed with a wide array of utilisable ordnance.    
That premise is only the beginning of a highly-replayable core concept, first thing you’ll want to try is the “Challenge Cup” campaign mode, which incorporates every map and every gamemode in roughly a difficulty curve to showcase the immense variety of experiences the game has: completing bronze, silver, and gold challenges on each map will unlock more and more playtypes, vehicles and maps for the campaign, while also unlocking new possibilities in the “Quick Play” casual mode with both pick-up singleplayer, cooperative- and competitive multiplayer.
After unlocking and completing a fair deal of the race challenges in the campaign, Quick Play really starts to come alive, the amazing variety of possible set-ups is what keeps this game fresh and fun after so many years – a far cry from the usual driving game clichés of dry, desert-industrial tracks and dimly-lit fenced-off cityscapes, Mashed brings in over a dozen highly-varied driving arenas that sweep a gamut all the most fun locales to motor maniacally around in; night-time oil rigs, an icy-slick wharf, an active motorway filled with pedestrian traffic, and the live battlefield were particular favourites of mine. 
Once you’ve found a niche map you love, you could test it out in Timetrial mode to get a handle on some of those trickier corners and then take the action to up-to-three other players or computer driven bots in a suite of gameplay objectives such as your standard demo-derby affair where points are lost for having your car destroyed and gained for not being similarly incapacitated - Survival mode, where you simply need to stay intact for a number of laps against an onslaught from the other cars to win, Fugitive mode, where you must either non-lethally pin a single car from escaping you, a boss battle feature where you do deadly battle with a circling helicopter – and these are just the surface of the gameplay options, the many, many, other exciting mods which would simply take far too long to mention and describe all of, so you will just need to experience them for yourself.
Apart from just gushing on about the multitude of gameplay options ad nauseam, I ought to mention the controls and other technical aspects for consideration.  Firstly, it’s never explicitly stated, but is heavily implied, that the events of the game are part of some larger, in-universe, television show, that’s why the camera follows suspended in the air between the various contestant vehicles, as a camera feed from a trailing helicopter, rather than any fixed-position camera or continuous third-person view – an unusual and rather novel approach to the question of camera placement, which heightens the sense of the dramatic and cinematic nature of these vehicular spars, but can sometimes be unfortunately troublesome or less than ideal in providing a clear view of your position in amidst the carnage, but you will certainly come to be familiar with the unique camera motions after a short time playing, and manoeuvring around it will become second nature to you.   
The simple controls are easy to get a hold of, the quick paced nature of the game means it can be picked up for ten, twenty, maybe thirty minute games at a time as a relaxing intermission, the car-combat is appropriately punchy and cathartic, and the sheer volume of different content available ensures long- lasting replayability, the 2004 graphics hold up remarkably well (especially considering the distance from which you view the car models), and the game will run perfectly on virtually any modern system, the only downside to this aged release is the lack of full Steamworks integration (ie. No Achievements or Trading Cards) but don’t let that stop you from picking up this fantastic bargain-price gem.
Very strongly recommended.