In 2384 AD, a great interstellar war took place. The Earth emerged victorious, thanks to a secretly developed robot weapon called "Serd". After the war, the usage of Serds was not a secret any more, and various nations started using them for military purposes. Several years, a more powerful weapon named Vector was developed. The usage of such highly destructive weapons led to wars between the nations of the world. You control Takuya Murasawa and his comrades, member of a special military force called Slash. Everything begins with an attack of unidentified Vectors on their base...
Vixen 357 is an anime-style tactical role-playing game with mecha combat. The player controls mechas by moving them over the battle map, and fighting enemies with long-ranged or melee attacks. An animated battle sequence is shown when the mechas attack each other. It is possible to switch pilots in the mechas and repair them during battles. The pilots level up by gaining experience points, and the player gradually gains access to new robots and weapons during the game.
Description from MobyGames