I sincerely apologize. A critical bug has been discovered and fixed belatedly.
Symptom: Items that cannot be purchased more than once would not appear in the shop, even when the player had not purchased them. Ex) Mythic items, and cloud-type summons which had an unmarked no-duplicate-purchase restriction.
Cause: The purchase history was not being reset between runs. It was only cleared when the game was fully closed.
What players experienced: No issues during the 1st run. However, if you started a 2nd run without closing the game, items purchased (and not sold) during the 1st run would not appear in the shop. In the worst case, if you purchased all Mythic items during an Endless Mode run, no Mythic items would appear at all in the next run.
Fix: Added purchase history reset functionality. Unique items now correctly appear in the shop every run.
I had previously received reports about this issue but was unable to reproduce it and regretfully left it unresolved.
While playtesting for reference material for my next game, I personally experienced this problem — Frost Hammer did not appear even after over an hour of play. Remembering that I had purchased it in a previous run led me to the fix.
It pains me to realize that this issue did not affect casual one-time players, but rather the dedicated players who loved the game enough to play Endless Mode and multiple runs.
I sincerely apologize for the delayed fix.