2 odcinek

itempools.xml

<ItemPools>
  <Pool Name="treasure">
    <Item Name="Carpet Bombing" Weight="1000" DecreaseBy="1" RemoveOn="0.1" />
  </Pool>
</ItemPools>

items.xml

<items gfxroot="gfx/items/" version="1">
	<active description="Fire in the hole" gfx="Collectibles_CarpetBombing.png" maxcharges="4" name="Carpet Bombing" />
</items>

main.lua

local tutorial = RegisterMod("Tutorial", 1)
local tutorial_item = Isaac.GetItemIdByName("Carpet Bombing")

tutorial.isFiring = false
tutorial.frameCounter = 0
tutorial.frequency = 2
tutorial.limit = 50

function tutorial:useItem()
  self.isFiring = true
end

function tutorial:handleTimer()
  if(self.isFiring == false) then
    return false
  else
    if self.frameCounter % self.frequency == 0 then
      local pos = Vector(math.random(0,1280), math.random(0,960))
      Isaac.Explode(pos, Isaac.GetPlayer(0), 100)
      if self.frameCounter / self.limit == self.frequency then
        self.isFiring = false
        self.frameCounter = 0
      end
    end
    self.frameCounter = self.frameCounter + 1
  end
end

function tutorial:stopDamage(entity)
  if(self.isFiring == true and entity == Isaac.GetPlayer(0)) then
    return false
  end
end

tutorial:AddCallback(ModCallbacks.MC_POST_UPDATE, tutorial.handleTimer)
tutorial:AddCallback(ModCallbacks.MC_USE_ITEM, tutorial.useItem, tutorial_item)
tutorial:AddCallback(ModCallbacks.MC_ENTITY_TAKE_DMG, tutorial.stopDamage)

metadata.xml

<metadata>
	<name>tutorial</name>
	<directory>tutorial</directory>
	<description/>
	<version>1.0</version>
	<visibility/>
</metadata>