Since I know that not everyone loves riddles, I made two options for people that don't like them.
1. The walkthrough has the solution and explanation for all difficult riddle areas in the FAQ section at the bottom.
2. You can find 3 "Riddle Key" items in the game, which automatically solve a riddle and allow you to pass through that area. The keys are limited, so that people will at least try to solve the riddles before using the keys, but it should be enough to get you through the harder riddles.
I hope this helps, and lets you enjoy the game again.
I don't remember the exact thoughts behind it, but it was probably for balancing reasons. But I agree that the logic is questionable. XD
I don't have a list at hand, but you can't find all equipment in the current battles. I left out some of them, since I need rewards for future battles.
I can't say for certain, since I didn't make the compressed version, but since my update files are for my normal upload (= not compressed version), I'd strongly assume that they don't work together with the compressed version.