I've played UhhClem's solo variant a few times, and I think I'd like to make a "Not quite heroic" variant. Something with the same basic setup, but slightly more winnable. Right now I'm thinking about One of the following. (Obviously this could be used in a standard 'heroic' game, too)

1) During setup, make only two cities have 3 cubes (4 cities with 2 cubes).

2) Lower the penultimate infection rate (from 4 to 3).

3) (The one I find most intriguing). Once during the game, a player may take a fifth action.

I like the idea of the last one, because it increases the scope for player arguments/decisions. A single action can often mean a cure (or eradication). Anyway, just tossing the idea out there.

This worked pretty well ... we lost, but it was a close thing. The fifth action let us cure our second disease a round earlier, and if we didn't get an epidemic followed by infection on 1 card (out of ~20), we would have survived the round necessary to cure two more diseases. Without the fifth action there was never hope.

I think that the leap from five to six Epidemic cards is huge. It's not so much that the sixth Epidemic is bad; it's that the fourth one comes before you're 2/3 of the way through the deck. I like the idea of delaying Infection Rate's leap to 4 cards by one Epidemic when you're playing at Heroic level: it'll be less hard, but it's still not going to be easy.

I find Heroic difficulty with 4 players to be the best!
I lose FAR more often than I win, but I enjoy the challenge, and it makes winning that much more exciting.

What if you made six piles(Heroic) but only the top five had Epidemic Cards? Same amount of Epidemics as Normal but at the same rate as the first 5 Heroic Epidemics. The only thing is you get a bit of a respite during the last 1/6th of the player deck if you make it there.

This is harder than Normal and not as hard as Heroic...I think