Level per monster kill?
 

I played my 1st game of Munchkin loved it!!! I had a quick question. I kicked the door Office Zombie turned up I could defeat. A player added wandering monster with nurse which i asked for help. Then another player played with a big whistle along with pizza guy luckily no other monsters were added and we were able to raise our combat strength to take care of it.
My question is would I get 1 level or since there were 3 monsters 3 levels?
If the answer is 3 what about my helper (Because of pizza guy)?

Re: Level per monster kill?
 

Would gain as many levels as you defeat monsters. There are some monsters that give more than one level.
Your assistant would win only one level.

Re: Level per monster kill?
 

So for your example, you get 3 levels and your helper gets 1 level. Provided neither of you are now Level 10 (in which case, the Level 10 player/s won the game), you now draw 6 Treasures face-up and distribute them between you as per the deal you made.