Avoid (and kill, if you can) the enemies whilst saving innocent bystanders and collecting theme cards. You can use arrow keys or WASD to move, or enable mouse movement. Once you collect certain cards, you will be able to attack (C, or click if mouse enabled). Try to collect all 50 cards.
A few more card implementations added, ordered into a more coherent sequence (where needed); some minor updates. Also includes health and resistances for some enemies.