Alexia's first form is actually intimidating, especially if the player is playing the Battle Game with Wesker (who's only weapon is a knife). Should the player gets too close to Alexia, she will grab the player, raise them from the ground, and do the Body Ignition attack, causing instant death. The trick is pretty simple; stay away from her to avoid being grabbed. Alexia will also spray her combustible blood in a vertical or horizontal manner. An easy way to defeat her is to use Shotgun or Crossbow loaded with bowgun powder. The player should keep their Colt Python and Grenade Launcher for her next battle.
Alexia's second form is noted as one of the hardest bosses in the Resident Evil series. With her ever-spawning ant minions dealing continuous damage to the player and giant tentacles whipping and slamming the battleground. However, there are ways to defeat her easily despite this.
Alexia's upper body is actually her weak point and shooting her in her upper body inflicts the most damage. To do this, the player must get close to her and aim up to ensure the weapon hits her. It should be noted that the player will take some damage doing this and should have some healing items in case of this.
About five to six Grenade LauncherExplosive Rounds to her upper body will make her go to her third form provided that Chris is close enough for all grenades (the CV Burst rounds have spread and fires multiple projectiles at once) to hit at once with each shot.
Interestingly, the Colt Python actually does less damage to Alexia than on other enemies, even when she is shot in the face with it, with two nearly full clips not damaging her as much as the grenade launcher rounds do.
Alexia's third form doesn't require much strategy in CODE: Veronica's story mode, as the player can simply fire the Linear Launcher multiple times and eventually hit her with it. However, Chris's version of the Battle Game features Alexia's second and third forms as the final boss, and the Linear Launcher is unavailable in the Battle Game (unless the player has cleared Battle Mode with all characters getting an A Rank).
Since Chris's ultimate weapon is unavailable, he will have to resort to using his Shotgun or Colt Python. The best way for this to be pulled off is by getting in close and using the change aim button and pressing it repeatedly. This takes a long time and can be frustrating but since Battle Mode has infinite Ammo for all weapons, the player can continuously fire. Blood will spurt out of Alexia 3's body when she is hit. Eventually, she will be defeated if the player continues to use the change aim strategy. When killed in Battle Mode, a cutscene triggers where Alexia 3 will fall on the ground and die squirming similar to a dying insect.