Let's start by saying, that if this game had come out before half life, it would had been the grand messiah of FPS genre, just as Doom and Half life are seen now.
It is hard to understand how many things this game gets right, I won't comment the story yet for I haven't completed the game (feels like your usual mecha-anime stuff). But as for levels, the design is rather good and entertaining. But what I really think hits the spot are the weapons, they kick ass. For they really do feel powerful, usually what it needs to take down a light armored target is two rounds from assault rifle, one if you hit chest or head. Armored targets take few more rounds, but they also go down fast. And also, you are a light target, so watch those corners and doorways, this is no quake. I was very surprised how much fun it was :)
The things change when you fight with your MCA (Mobile Combat Armor) most of weapons do some sort of area damage, enemies and yourself take some heavy punishment and fighting takes place in cities or wastelands, you get to choose from 5 different mechs with varying armor and speed characteristics. Take note though, this is no mech "simulation", action is pretty straight forward and works just like you would be infantry.... except you can destroy enemy tanks and MCA's with a giant robot packing lots of firepower from rockets to large laser rifles, and a sword (it's anime, go and figure). It's all fun, I knew this game was rated high back in the day, and I know it got good grades in GoG, but I was still surprised by this title. Sure the graphics haven't aged well, but if you can see under the old graphics engine, there's a very entertaining and solid game underneath :)