anchor.diff:      bool hero_is_dead;
       bool game_over;
       int monsters_killed;
  +    GridPoint last_monster_death;
       Random rng;
   
       DungeonState(this.dg)
  
positive.code:                 } else {
                      monsters.remove(to);
                      monsters_killed += 1;
                      dg.drawGridSquare(to.location);
                  }
              });
  
negative.code:     }
  
      void heroInput(Input input) {
          if (hero_is_dead) {
              dg.status.updateStatus(dg.ctx, "You died. Restart if you want to play again.");
              return;
          }
  
          if (game_over) {
              //dg.status.updateStatus(dg.ctx, "You killed all monsters. Restart if you want to play again.");
          }
  
          if (!hero_turn) {
  