Hello Adam,
First of all, congrats on the programming of Potion Explosion : it is beautiful, and smooth ! One of the best experiences on BGA.
However I think there is a minor bug (I checked the rules) : when the game is almost completed, if there is no more "skills tokens", the game still "create" new ones to complete our score. Please find included an example of a game of 2 players, which should have only 4 tokens, but here at the last turn, we manage to finish our potions, so the count go up to 7 :-/

- BGA_Potion_explosion_bug2.png (19.94 KiB) Viewed 842 times
[EDIT] : Adam answered by email, and I include the snippet as a image joined to my message.
The issue here is not actually a bug but a misunderstanding of the skill token stack. It is simply there to identify the game end trigger, however skill tokens are still available from the ‘general pool’. I have copied the snippet from the rule book for you for reference.

- BGA_Potion_explosion_rules.png (79.96 KiB) Viewed 835 times
Thank you for you time, I played twice already and had a lot of fun !
Bests regards,
Steph