Pretty repetitive, but overall a good game.
The game is broken into two major parts. One part is where you do the actual fighting in your 'Mech. These battles take place in flat, Mode 7 areas set on the many different chaotic planets that are in need of mercenaries. The player controls the 'mech and uses it to move around the mission area, and battle other 'mechs that need to be destroyed to complete the mission. Some missions require you to find an artifact hidden inside one of the enemies, or to defend a structure from attack. However, they all involve blowing up other 'mechs, and...blowing up other 'mechs. The controls are unusually responsive in this game, which really helps when you need to do some fancy maneuvering to get out of a tight spot.
The other part of the game deals with the story, meeting other characters, and 'mech maintenance. Your character has access to the Zero-Zero Bar, which is used to find clues to the whereabouts of the Dark Wing Lance and meet people that can give you special missions. This bar can also be used to listen to the news and read more about the Mechwarrior universe if the player so chooses.
The player also has access to the General Headquarters, which is where contracts can be accepted. Every mission in the game is contractually agreed to, and after each one you are paid the agreed upon amount (which is slightly negotiable) for your services. Finally, the player also has access to the 'Mech Bay, which is where 'Mechs can be bought, sold, repaired, or modified. You can buy all sorts of missiles, energy weapons, armor, and other equipment to outfit your 'mech. There are weight restrictions on each 'mech though, so decisions about equipment must be strategically thought out.
It is interesting to note that, if desired, the story of the game can be completely ignored. You never have to visit the Zero-Zero Bar if all you want to do is shoot up 'mechs and earn some money. Unfortunately, the difficulty of the missions increases every time one is completed, so if you aren't careful you could end up with an impossible challenge on a game you can never really complete. Also, the battles can get very repetitive, broken up only by the occasional Dark Wing Lance boss fight if you are following the story.
Graphically, the game is not very impressive. It doesn't need to be though, as the meat of the game lies in the battles, which are a lot of fun to fight. However, the sound in this game is AWFUL. All of the music is quite dull and boring, and the sound effects probably could have been done better.
In all, Mechwarrior is an enjoyable and fulfilling experience for anyone that is a fan of giant fighting robots.