Arduino Game

#include <LiquidCrystal.h>
#include <Wire.h>
#include <ArduinoNunchuk.h>

ArduinoNunchuk nunchuk = ArduinoNunchuk();
LiquidCrystal lcd(2,3,4,5,6,7);

int posX = 90;
int x = 0;
int x2 = 0;
int prevx = 0;
int prevx2 = 0;
int prevPosX = 0;
int zState = 0;
unsigned long previousMillis = 0;
long interval = 500;
int i = 0;
int j = 0;
int score = 0;

byte enemy[8] = {
  B01110,
  B10001,
  B10101,
  B10001,
  B10101,
  B11011,
  B10101,
};

byte gun[8] = {
  B00000,
  B00000,
  B00100,
  B01110,
  B01010,
  B01110,
  B11111,
};

byte full[8] = {
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
};

byte empty[8] = {
  B00000,
  B00000,
  B00000,
  B00000,
  B00000,
  B00000,
  B00000,
};

void setup(){
  Serial.begin(9600);
  lcd.begin(16,2);
  nunchuk.init();
  lcd.createChar(5, enemy);
  lcd.createChar(1, gun);
  lcd.createChar(2, full);
  lcd.createChar(3, empty);
}

void loop(){
  nunchuk.update();
  x = constrain(x, 0, 14);
  x2 = constrain(x2, 0, 14);

  lcd.setCursor(x,0);
  lcd.write(5);
  lcd.setCursor(x2,1);
  lcd.write(1);
  lcd.setCursor(15, 0);
  lcd.print(score);

  zState = nunchuk.zButton;

  posX = nunchuk.analogX;

  if(zState == HIGH && x == x2){
    lcd.setCursor(x,0);
    lcd.write(2);
    delay(333);
    score++;
    x = random(0,15);
  }

  if(posX < 60 && prevPosX > 60){
    x2--;
  }
  if(posX > 200 && prevPosX < 200){
    x2++;
  }

  unsigned long currentMillis = millis();

  if(currentMillis - previousMillis > interval){
    i = random(0,2);
    if(i == 0){
      x--;
    }
    if(i == 1){
      x++;
    }
    previousMillis = currentMillis;
  }

  if(zState == HIGH){
    lcd.setCursor(15,1);
    lcd.write(2);
  }

  if(zState == LOW){
    lcd.setCursor(15,1);
    lcd.write(3);
  }

  if(score == 9){
    lcd.setCursor(0,0);
    lcd.print("   GAME OVER    ");
    lcd.setCursor(2,1);
    lcd.print(currentMillis / 1000);
    lcd.print("  Seconds");
    lcd.setCursor(15,1);
    lcd.write(3);
    delay(5000);
    score = 0;
  }

  if(x != prevx ||  x2 != prevx2){
    lcd.clear();
  }

  prevx = x;
  prevPosX = posX;
  prevx2 = x2;
}