Thanks for your feedback! I am no pixel artist by any means - this was bothering me a bit as well^^ I could probably manage to come up with the overworld sprites, but not the front and back sprites :/
Generally, you simply give them the item they would require for a trade evolution, similar to e.g. a Water Stone. For classic "trade" evolutions, you can buy the link cable item that was first implemented in Legends Arceus ;)
Which move in particular did you not take recoil damage from? Or was it on your Basculin? They can have "Rock Head" as an ability, which prevents them from taking recoil damage!
As for evolution methods:
Runerigus needs to take damage (I think it is 49 points) and then either bring it back to...
I suppose you were able to solve it with the hints/solution from my DM :)
I just uploaded the latest version 1.04 which SIGNIFICANTLY reduces the game's file size from previously 1.5GB all the way down around 500MB by compressing tons of music!
The difference for MOST fights in hard mode is "just" a slightly higher level, however I agree with you, that fight is quite tough early on. However it is by design that I want to leave the player with the thought of "maybe I should continue elsewhere first" from time to time - at least in the...
I managed to quickly fix the bug and upload the latest version 1.03 tonight for you - even if your Purple Gem is currently stuck on the socket already, you should now be able to pick it up and solve the puzzle - you might just end up with a spare Purple Gem in the end... :)