I loved this game when I played through it many years ago. Steep difficulty curve but balanced out by being able to save wherever you like, so if your plasma grenade only knocked out 3 of those 4 Borg drones you can try again until you get it right. Brutal vision cones (especially in the later levels!) meant pushing forward sometimes literally step by step was a big feature. Just don't get caught phasering too many Klingons or your mission is sure to fail!