There are seven weapons in Death Blade (counting your hands as deadly weapons). Four of these weapons are magical and serve special purposes. You will find that no single weapon is good to use against all creatures. Some weapons do double damage against certain types of creatures, while others may actually heal you in a minor way, each time a hit is scored. It is up to you to find out what each weapon does. Don't worry, the name of the magical weapons, should give you some clue that can aid in your research.
To switch weapon, press the <TAB> key. This will advance to the next weapon in your possession. If you are on the most powerful weapon you possess at the time you hit the <TAB> key, the display will wrap to display "Hands". This quick interface design prevents you from having to open your inventory and equip weapons. A design that many games seem to prefer using.
Armor
Armor is not something you keep in your inventory. It is not something you select in a list of items. Therefore, Death Blade does not bore you with having to manage it. When you find better armor that you are currently wearing in a treasure pile, your character will automatically put it on, improving his armor class. This is one less thing you will have to worry about, allowing you to focus on the quest at hand.