OpenXcom is a fantastic reimplementation of the original, and has some even more fantastic mods. I agree if you’ve never played it before and aren’t too familiar with old school “Nintendo-hard” games, it can be extremely challenging even on the lowest difficulty. Fun fact, the original had a broken difficulty selection and reset to the “easiest” difficulty after reloading any save game, so most people never truly experienced a full run at any difficulty above “easiest”, so that’s just naturally perceived as the way the game was meant to be balanced. Don’t be ashamed of playing on the easiest difficulty or using “cheat” mods if that’s what makes it playable for you. There’s nobody to judge you but yourself and what matters is that you’re having fun. And it is a ridiculously fun and replayable game, to me at least.