There is no cheat menu, cheat codes, or unlock-all command in Ben 10: Vilgax Attacks on Xbox 360. The game uses standard progression: complete levels → unlock aliens / upgrades / concept art.
No save editor / profile editor exists publicly. You'd need a modded 360 (RGH/JTAG) + memory edit — not worth it for a 6-hour game.
Play it. It's short, colorful, and the alien variety is the fun part.