Go to the haunted forest, go deeper, then go LEFT LEFT RIGHT LEFT 

you must click yes to continue

go to monke hq and get the key

then it should bring you back to the fun fun fun guy

im stuck here so...

You need to go into act and heal yourself. Heal yourself to a comfortable amount, he only does 60 damage. Once thats done go into act and spam tire until the game tells you you can spare him. Spare him and go get the gun, then kill the weed man and go to the abandoned shack at the beginning of the haunted forest. Go into the basement and click “Use shard” and you get the ending.