I'm doing well, merely super short on time. Lots of things to do at work. It has been extremely hard to find even half a day to continuously attack a hobby project.

Some levels that may warrant investigation for 100%:

• Tubelectric 2: Allegedly some unreachable items or wrong count in some version.
• Nippius 2: Can't reach all ice creeam cones during a single jump at the exit.
• Battleships 2: No claims I've heard. But there are two different paths through Battleships 2, and both eventually prevent backtracking.
• Deserto 1+2: No claims I've heard. But sparkles in this world generate unlimited lizard enemies. The sparkles themselves can be killed. How do either of these count towards 100%?

Enemy count differs across difficulties. If one wants to be ultra-thorough, one would have to 100% the maps on several difficulties. I'm rather certain that Hard and Turbo have the same enemy distribution in all levels by Epic and Turbo merely adds 1 HP to all enemies.

Extremely unlikely, but theoretically possible, is that the treasure distribution depends on the difficulty. Consider that Dreempipes 2 has Launcher ammo containers that only appear on Hard and Turbo, at the start of the final horizontal yellow pipe section. Likely, the level format allows not merely ammo containers, but also treasures to depend on difficulty. But I would be very surprised if it ever happens throughout Epic's levels.

-- Simon