okay for awhile now there has been an exploit, where if you feed waldenbrooke(or any merchant) with a lot of si's, you can easily level him up to huge amounts. You can then use door creation to sacrifice him easy, taking you from level 5 to 50 instantly, and destroying all the games challenge.
but it gets worse, If you wait to level 50 and play as necromancer, you can feed him a lot more, and use their level 50 power quickly hold down button and kill him, maxing xp to 999999999999999. This inflates the highscore and makes it so a regular gate close can get 4x more score than even the best Ultra Chaos God ending. You can even suicide so many times that you create a bug on necromancers level 50 death penalty and giving you infinite health/stats for easy casting.
We have two scores on the list that demonstrate the exploit
First we have Grond's "waldensplat" using the technique to its greatest potential so far, as a necromancer killing waldenbrooke himself, and bugging the death hp penalty to health/book cast ball spells infinitely, and do it in low turncount, was able to almost get 4x as much as the highest Ultra Chaos God ending.
We also have Psy_wombat's "glitter" that also used a variation, except instead of killing waldenbrooke, he sacrificed him, still netting him millions of points more than regular gateclose and almost reaching the highest Ultra ending highscore.
I suggest removing the artifacts leveling shopkeepers, and deleting the highscores that use this.
If it is kept in game, the highscore list will be nothing be gateclosing necromancers eventually, that all did the shopkeeper exploit. (you don't get as many bonus highscore points in ultra endings for xp, like you do in gate close victory, so this exploit is not possible to do as well on ultra endings)
demonstration of the necromancer exploit (and current high score)
https://www.twitch.tv/videos/210452617
http://ancardia.wikia.com/wiki/Waldenbrook_sacrificing
wiki page with easy strategies on the exploit.