Huge upgrade over Kz-2. Game is non-stop action with clever level design and diverse missions.
The story and characters are nothing great but they do not weigh down the experience in anyway. The weapons are similar to the last one. The enemies are slightly more diverse than the last game. This time you will encounter more flying drones to robot spiders.
Perhaps the biggest weakness are the very easy boss battles and even easier enemies. You should fly through this game with little difficulty on normal setting. No section is 1/10th as hard as the famous Radec boss battle in game 2. Also the characters are very annoying after awhile. Same one dimensional characters and dialogue. Most of the dialogue can come off as pretty corny. The super easy enemies makes the game too easy on normal mode.
Overall, the game is a huge improvement over the famous Kz-2. The game provides fun weapons, creative environments, diverse missions and non stop action. The game has great graphics and is far more polished than KZ-2. The controls are much easier to use as well. The length is a solid 10-12 hours.
I am glad I bought it and the single player is very good.