Some sci-fi games seem to focus solely on killing tons of aliens, usually in a first-person view, a la Doom, or real-time strategy, as in Starcraft, but few merge tactics and squad-based play like The Red Solstice. Though you're in charge of squads of marines, don't think you can blindly charge through the creatures, firing hundreds of rounds of bullets into each monster. The sheer number of beasts that swarm through the 10 missions of the single-player campaign or that randomly spawn during the survival or multiplayer modes will tear your soldiers to ribbons, forcing you to reload and start again. To have any kind of success, you need to cautiously enter battle, using the skills and weapons of the eight classes of marines to gain ground, set up forward positions, and frequently repel waves of incoming monsters that throw themselves at you before you can successfully accomplish your objectives. It can be a step-by-step grind to complete some stages, even forcing you to strategically retreat to ammo stockpiles to rearm your grunts before clearing out a difficult checkpoint.
It's not simply the checkpoints that are challenging. The Red Solstice is a very difficult game. It doesn't matter how many times you go through the tutorials or attempt to follow some of the cautionary prompts: One tactical error, one lapse in your firing line, one mistake in triggering a skill a second too early, and even the best-laid plans collapse in a flood of aliens overrunning your position. You may even find that your AI will make some stupid decisions, disregarding some commands and leaving some squadmates behind to die. But most of these problems can be tied to mistakes you've made during the mission. If anything, the extreme difficulty makes successful completion of an objective or mission more enjoyable and drives you to keep playing even when you find yourself extremely frustrated. The challenge may keep some players away, but strategy and sci-fi fans should definitely put The Red Solstice on their lists.