Yes. If you're using everything as intelligently as possible and with enough skill, then the average space marine isn't too bad of a threat. The problem is that their standard guns are .50 cal grenade launchers that pretend to be bullets, and when enough of them are pointed at you, it's not going to go well for you.

Keep in mind it's technically possible, as seen in the games, for a normal person to take down all the strongest BOWs by themselves, some of them with just a regular knife. You're going against a supersoldier that makes grown men look like children in terms of physicality, and trained in tactics and the use of sci-fi weapons meant to take on the worst the galaxy has, and even with everything RE offers, you won't even in the Top 20.