EoSD? Not really. Its probably the hardest windows game outside of UFO. Bullets slow in EoSD? I wouldn't say they are. There are cases when the bullets are slow but then there is usually something else that makes things harder.
Back when i was a normal mode aspirant i had the hardest time clearing EoSD and SA.
EoSD Lunatic is probably the hardest non-UFO one.
I'm not saying that it's any easier objectively speaking because it's slower,
although for beginners, *slow* bullets, I think, definitely help because their eyes aren't as used to it yet.
When I first played, I had a lot of trouble with Eternal Meek and Flower Dream Vine (hard),
as they seemed really really fast, but after I 1cc UFO, and then go back to play, they are much more manageable.
Would EoSD still be that hard if you play with 5 lives instead of 3?
One of my main gripes about it was the (comparably) lack of resources for the difficulty,
having only 6 extends and 3 extra bombs (some are weak too).