Moonstone

Let us talk about Moonstone. An Amiga game from 1993, now abandonware, it puts you and your friends into the role of one of four knights whose goal is collecting the keys to the village to obtain a Moonstone and become a god. This can be done alone or with up to three other people.

You fight all kinds of monsters and even your own friends. Every so often, a lair gives you a key. Four of these keys give you access to the fight with the guardian, a milestone in each playthrough since you need to defeat it to get the Moonstone.

The variety of enemies is rather colourful. You face the humanoid-like Troggs, mudmen who can instantly drag you in the mud and ratman who can hang you with their tail until you face the dragon, which has unbelievable riches if you defeat him. This brings me to the graphic violent this game displays. Every way you die is a rather brutal one, whether it be burnt, smashed or beheaded.
From moonstonetavern.co.uk:

Luckily, you have a wide selection of attacks you can use to fend off your foes. You can use a stand horizontal swing, a powerful overhead swing, a lunge attack and you can even throw daggers and block.

Several items and scrolls can be bought to make the life of a knight easier. A dragon talisman for example lets you take less damage from the dragon's firebreath, a crystal orb lets you see what treasures a lair has for you, and a magical ring increases your life capacity. You can also upgrade your sword and armor and increase either your STRENGTH, CONSTITUTION or ENDURANCE stat.

If you want to try it out yourself, check http://www.moonstonetavern.co.uk/emulation.htm
The game is free to download now and a user provided a trouble-free solution in case you do not want to tinker around with the amiga emulator.