Enemy Destruction via Bullet in CC

--[[ Method: Game Object Tables ]]
-- go through the "enemies" table
-- backwards, so we can efficiently remove objects, and there will be no skips
for enum = #enemies, 1, -1 do
  local enemy = enemies[enum]

  -- all of your enemy creation/moving code

  -- go through whatever table holds the bullets
  for bnum = #bullets, 1, -1 do
    local bullet = bullets[bnum]

    -- check if they are touching
    -- for this, I assume that everything takes up only one character
    -- use whatever method fits you, however
    if bullet.x == enemy.x
    and bullet.y == enemy.y then
      -- destroy both the enemy and the bullet
      -- by removing them from their respective tables
      table.remove(enemies, enum)
      table.remove(bullets, bnum)
      break

      -- alternatively, you could use a health system for enemies.
      --[[
      if enemy.health > 0 then
        enemy.health = enemy.health - 1
      else
        -- the removing code above
      end
      --]]
    end
  end
end

--[[ Method: Game Object Grid ]]
-- go through all of the grid squares
for y=1, #grid do
  for x=1, #grid[y] do
    -- we assume that each grid space has a "type" property that tells us what's there
    if grid[y][x].type == 'enemy' then
      -- for this, we assume that the player is shooting bullets from the bottom
      -- therefore, any bullets will be below us
      -- so we check that space, which is at x, y + 1
      if grid[y + 1] and grid[y + 1][x] and grid[y + 1][x].type == 'bullet' then
        -- then, erase both the enemy and the bullet from the grid if they are both in the right position
        grid[y][x] = nil
        grid[y + 1][x] = nil
        break
      end
    end
  end
end