I hit the same soft-lock error. I didn't have a wormhole potion, but I explored the whole map and bumped every wall to see if maybe there was a new type of secret, but no. The game ended there for me.
you just gave us a neat idea e.e
As mentioned in the comment above, the necromancer is the last boss of current build, we have been working really hard on the next update that will come in the following week with more levels, items, 1 extra boss and a reworked inventory.
Thanks for playing our game and hope you hade a good time n.n