My first XCOM playthrough on Classic difficulty very nearly ended in disaster. I screwed up in the very first month by choosing $ over engineers, with the result being that I had no satellites at the end of the first month and only one at the end of month two. By the third month, I had lost every single country in Africa and South America (including my base -- a UFO shot down my preexisting satellite over Argentina; I don't know how the hell I was supposed to prevent that so early in the game). I was dangerously close to Game Over.
Fortunately I managed panic so as to keep all my losses contained to specific continents. Now I'm just a couple weeks away from getting satellites up over every remaining country but one, and I'll take care of that one next month. And I managed to get two snipers equipped with Double Tap and plasma sniper rifles, which means they're at that point where they absolutely wreck every alien that comes into their line of sight. And this is with the alien base mission coming up next. Quite a bit of the story left to go, but I feel like I've basically got the game won now.
Classic is such a huge step up from Normal that it's like a different game. I absolutely have to stun aliens for their gear, because the stuff you have to buy eats up so much of your budget that you just can't pass up free plasma rifles. Resources and cash are really hard to manage in this one, and I ran with default weapons and armor seemingly forever before I got my firepower up. Doing this on Ironman would be super-hard since relatively small mistakes or even just unlucky rolls are catastrophic when you're that underpowered. Now I understand all the posts about how it took people 10+ tries before they beat Classic Ironman.