Xcom is damn hard.
This game is hands down the most fun I've had in a strategy game ever. Turn-based, yet gives the illusion of action that is a real nail-biter. Planning your research is everything, and everything takes time and money to make. Time may be your worst enemy, but there are some ways around this such as continent perks and getting more scientists and engineers on your team. Eventually you will start having your squads wiped out, which is really hell since your leveled up soldiers become very important to completing mission, and you'll have to master the strategic combat just to make it out alive. If the traditional challenge isn't enough you can go for classic and impossible modes which boost the alien's ability to kill you. And if that's not enough play Iron-man mode which take away your ability to reload old saves. It's simply sadistic, but if that's what your life has come to then this is a game for you. This game will have you frustrated but not lose your interest anytime soon.