Just sayin, ive played and beat ME1 9 times and played and beat ME2 5 times, and both go a little something like this: Easy - normal difficulty any class is op, personally most fun class is pure biotics with both and on the first game, if you want it to be a friggan cake walk, go wrex and liara as squad mates and max out everyones warp, push, and lift abilities ASAP, on the hardest difficulties, if you use anything but the soldier/assassin(sniper) class you are setting yourself up for failure, literally does the most damage without hitting anythine with warp (which does something around the area of 70% increase in damage with all weapons and attacks, which becomes useless on harder difficulties beacuse it doesnt WOOOOOOOOOOORK >.>) If your playing on hard like a real man, stay the hell away from the enemies, do every side quest you can to get levels, make sure you teck up someones abilities to do the lock hacking and the tech salvaging (cant remember what those be in the first one, youll figure it out.)
GL