Resources on earth are running out, human beings must find a new planet to live on. It is fortunate that a planet like Earth was discovered, but unfortunately, some organisms have been living there and they didn’t welcome us. Our first settlers were attacked violently. You, as a commander, must protect your base by using your limited resources. Dispose weapons in front of fortress to avoid monsters.Weapons are in grades. (Tips: Only the primary weapons can be disposed directly, the secondary and higher level weapons can only be disposed on weapons of previous level. For the specific details, read the tips of each weapon.)