Let´s devolve!

Here I have a fun little game idea for you. You will need a d4 to a d12.

First, realize the following, this is a barebones idea of a system, still, with a good DM this is as playable as everything else. It wil basically be a fantasy game but surely the idea is adaptable.

Give a player a sheet of paper.

Let him write a name of his character. Nicknames are better, but normal names will also serve.

Now he chooses his class.

He can choose Warrior/Wizard/Thief.

Each class comes with its own way of play and special abilities.

This is important because it explains why every player needs his own set of dice.

Warrior

He gets the d8 for hitpoints per level.

He attacks with a d6. Every 5 or 6 is a hit. Every 6 he rolls is a critical. He gains a +1 to-hit per 2 level.

So at level 3 he hits on a 4,5,6 and on level 5 on a 3,4,5,6 etc...

If he makes a critical hit, he rolls the d4 for additional damage.

The d10 is the experience die. Everytime he has made 10 kills, he levels up and the die resets to zero.

The d12 is his potion die. Each time he levels up, he gains a potion. 

A potion restores a full die of hitpoints.

He can use all weapons (except 2 one-handed) and all armour types.

Wizard

He gets the d4 for hitpoints per level.

He attacks with a d6. Every 5 or 6 is a hit.Every set rolled is a misfire. He gains an additional d6 per level.

If he makes a set, the spell screws up spectacularly into the wizards face. 

The wizard takes as much damage as he has dice in the set. He can decide how many dice to use to attack.

The d12 is his experience die. Everytime he has made 12 kills, he levels up and the die resets to zero.

The d10 is his elixir die. Each time he levels up, he gains an elixir. 

An elixir allows a spellcast without misfire.

He may never use weapons or armour.

Thief

He gets the d6 for hitpoints per level.

He attacks with a d6. Every 5 or 6 is a hit. Every set he rolls is a critical. 

He gains an additional critical die per 2 level. 

If he makes a critical hit, he rolls the d4 for additional damage.

So at level 3 if he hits he does one damage but on a critical hit he rolls 2d4 extra. At level 5 3d4 etc...

The d8 is the experience die. Everytime he has made 8 kills, he levels up and the die resets to zero.

The d10 is his bomb die. Each time he levels up, he gains a bomb. A bomb destroys a full die of hitpoints.

He can use all weapon types (except 2-handed ones) and only light armour.

A warrior and thief may use weapons and armor.

Weapons make you stronger. A new weapon always adds a die to the attack.

You can only gain one new weapon per level. 

To gain a new weapon, you roll a d6. On a hit (5 or 6) you gained a new weapon. 

You do the same thing to gain armour. 

However, you may only roll for armour on the levels 5, 10 and 15.

Armour give the player a resistance save against enemy hits.

If an enemy hits a player, the player gets to roll for every hit made against him.

6+ for light armour. 4+ for medium armour. 2+ for heavy armour.

However, heavy armour takes away one attack die to use.

Enemies always hit on a 5 or 6 on a d6. 

There are at least as many enemies as the GM has d6 in his hands to roll. 

Sometimes more. Sometimes less.

In combat, everyone acts at the same time.

The game ends when the people playing decide, that they had enough.

So there you have it. A barebones version of a very funny game system possible to write on a few cards and bring to everywhere you want to play it. You could print it and start the fun. Go dungeon crawl!