Metal Slug X is an enhanced version of Metal Slug 2: Super Vehicle - 001/II. The main differences to the original release include:
- Additional weapons: Stones, Iron Lizard, Enemy Chaser, Super Grenade, and Drop Shot.
- Additional power-ups, items, and prisoners in most of the levels.
- Additional times of the day: stages can take place at twilight, sunset, or dusk.
- Some of the locations and vehicles in the game have been altered.
- Increased enemy count. Some of the enemies' placement has been changed.
- Many weapons have a stronger explosive force. Explosions yield more unexpected results.
- The soundtrack has been re-mixed.
