Press WASD to move, and use your mouse to aim your sword and click to attack. Kill all enemies on the floor to advance to the next floor. Then choose the perk you want by clicking on it. Once every 10 floors, you will face a boss and then get a weapon + you choose a perk for the enemies. After floor 20 you'll stop getting new weapons and after floor 50 you'll stop getting new perks. Beat floor 50 to beat the game. Technically the game COULD crash due to lack of enemy perk choices but nobody is getting to floor 200+.
This game is really hard; no choosing expert from the start. Also, no projectiles must be on the screen to advance to the next floor, as well as enemies, so stop shooting arrows for a moment.