Running low on energy or missiles can be a death sentence. To replenish your resources, you can 'farm' enemies. Certain enemies, when defeated, have a chance to drop small energy or missile pickups. Find a room with easily defeated enemies that respawn quickly (e.g., Zoomers or Skrees in Brinstar). Enter the room, defeat the enemies, collect any drops, then exit and re-enter the room to make them respawn. Repeat this process until your energy and missile counts are sufficiently high. This is especially useful before boss fights or venturing into dangerous new areas like Tourian where resources are scarce.
