Yeah, I think I wrote the part about it being hard to be left without attack spells before adding the Spellsmith, and didn't edit it later.
I now introduced a small change - if you only have one attack spell, and it is an advanced one, the Spellsmith won't use Smelt on you.
Also, smelted spells are restored after you beat the boss (right now it just ends the run, so you can't see it), so Smelt won't affect your chances in the next level.
Regarding Light and how it affects/doesn't affect enemy moves: if an enemy move has "Accuracy" mentioned in the description, it is affected by Light. If it has a "Success rate", it isn't. Some moves have none of those things, which means if the enemy uses them, they will always succeed (Smelt is one of those). It's similar with the spells and enemy moves that reduce accuracy - only offensive spells, which have "Accuracy" in the description, are affected by those.
As for going to the portal early - it most often isn't worth it, as you miss out on rewards, but in my playthroughs I sometimes found it necessary - for example, I only had offensive spells that stronger enemies on a particular level (which appear only in the later rooms) resisted, or I had no healing spell and limited Healing Shards.
About relics - staffs and wands have separate events, all the other relics are in one big pool and two random ones are picked each time you get the relic event. There are no set pairs.
Anyway, thank you very much for your feedback! I'll definitely be making balance changes to existing levels and enemies in the next big update, so it's great to hear from the players about that. (For example, I think I'll reduce the frequency of Crystal Anomaly's shard eating move).