I've been playing classic with every character. I've been on difficulty level 3 or 4 depending on how comfortable I am with the character. When characters got unlocked, I had a hard time beating them. I think it took 4+ tries to beat Duck Hunt.
I got curious and turned up the difficulty all the way to the maximum. I chose Zero Suit Samus, just because that was the next character I hadn't used yet. I ended up going without dying all the way to the boss. Then it got bad. I lost to the boss so many times the difficulty got all the way down to 5.something before I won.
Also, clearly when it comes to direct fighting 1v1 I also suck. I think I just don't understand even the most basic strategies of this game. I try to get near the opponent and attack in their direction. That's pretty much it. Against anyone actually good I can't seem to even land one hit, they dodge, block, or counter-attack. Meanwhile when they come to hit me and I try to evade, I get hit anyway.
Also, I've gotten used to the button controls, but not the analog stick. Far too often the game does what I don't want it to do. When I beat the game as Charizard I had the hardest time. His special right or left move has him flying very far in one direction. Every time I used this move it was suicide. He went straight off the screen, and I couldn't recover. W T F. I was afraid to use the B button at all in fear of doing that move by accident. And yes, it did happen by accident many times.
There are only three attack buttons in smash, attack, special, and grab. Yet, each button does so many completely different things based on whether you are airborne or grounded, whether running, walking, or still, and the movement of the analog stick. Thus, the precise and quick manipulation of that little pad counts for everything.
The biggest problem I have, with every character, is simply attacking in the wrong direction. Let's say I'm going left. I want to turn around and attack. I move the stick to the right and press attack. If I press attack slightly too soon (often) I'll actually attack to the left. Uncancellable attack animations will leave me completely vulnerable to the enemy on the right. The air will take a lot of damage, though. Even if I press attack during/after pressing right, milliseconds determine whether that is just going to be an attack, or a smash. If it's an unintended smash, and I don't let go fast enough I will be completely vulnerable charging up a smash. But if I'm Pikachu or someone with a rapid-fire attack, I WANT to hold down attack.
I was born too late for this shit. We need an old fogey's league. No kids allowed.