ok here are some tips (might contain spoilers)
Tip 1: The artifact Ernesh can lower by 1 the lEmOn´s irritation bi 1 if you get 7 answers right in a row. It´s price is 125 stars.
Tip 2: Bring 9 scissors from Mr TomatoS to cut the vines in round 5.
Tip 3: Maneki-neko can save you from irritating the LeMoN, and can help you in the battle by reviving you.
Tip 4: Get your body parts from Mr TomatoS. Get him to anger 10, then click on the hand and the eye.
Tip 5: Bring candy from Mr TomatoS. Bring 1, because you can only use 1 in the entire run.
Tip 6: Lamia´s Rock, Paper, Scissors is rigged.
Tip 7: If you buy the key leave it in Mr Tomatos by pressing E while holding it. Otherwise, if you enter with it, tHe LeMoN will notice, and will confiscate it.
Tip 8: If you try to stab ThE lEmOn, do it with the skull. Otherwise, you´ll get blocked from both games.