No, you must have been playing in a random-enabled room.
For the most part, player level is meaningless. Generally, level 50+ players are going to be tough, and level 15- players will be easy wins, but not always. And it has no effect on the game, except earning Leaders at certain levels.
No, the player's lever don't affect anything in the attack. Probably you're playing in a random room. Try playing in another room with a icon (dice covered with blood) and see that if you have higher attack points, you'll win for sure, but read the rules for better understanding.