First Impressions: Half-Life: Opposing Force

This is the first of the two expansion packs for Half-Life and places you in control of a US Marine (Adrian Shephard), which as the first game points out, is actually the enemy, hence 'Opposing Force'. This is interesting as it gives you a second perspective on the story you played previously in Half-Life (and of the soldiers that you previously just brutally murdered).
The great gameplay of the original game is still there (as are the not-very-good graphics). However, there are a few differences such as, being a soldier, you have an armoured vest rather than a hazmat suit (which gives you more defence than the hazmat suit but, I suspect, won't give you as much radiation resistance). However it does offer more protection, partly due to the change in stat from power to armour. For example the electric people no longer one shot me like in the previous game (it's more like three shots now). Finally, due to it being a shorter game, you get stronger (and different) weapons from earlier on and face stronger (and different) enemies as well.

The weapons I've seen so far are:
The wrench: a much slower, much stronger version of the crossbar. Hold the second mouse button for a one shotting hit!
The knife: much faster but with a shorter range and less power. But the speed is very helpful!
The laser pistol: now, this isn't a pistol that fires lasers but, rather, a pistol with a laser marker. And a higher caliber bullet.
The pistol: same as the last game. Still as good as ever.
The shotgun: ol' reliable right here.
The machine gun: and ol' reliable's best friend!
The rocket launcher: slow and powerful. And stupidly inaccurate at times.
Grenades: take out the pin. Throw the grenade. Watch as colourful bits of alien hit you in the face.
Bag o' explosives: place the bag. Run away. Press the ignition. Watch as colourful bits of alien hit the wall you've hidden behind.

And, the enemies I've seen are:
Face-Latcher: still resembles a roast chicken. Still tries to eat your face.
Zombie Soldier: this is what happens when a Face-Latcher and a soldier meet in unholy matrimony.
Sonic Dogs: these dog like creatures can set off a sonic boom that does a lot of damage (but you can hit the creatures in order to stop their attacks). WARNING: guilt may follow their adorable cries.
Electric *?!£$%: these are still the bane of my life but at least I'm not one shotted any more.
Friend Killer: these creatures deserve to die for what they did to John. Poor guy.
This-Isn't-Even-My-Final-Form: these creatures are what happens when the Zombie Soldier/Scientist has been completely consumed by the roast chicken.
Speedy Mcspeederson: these fast aliens run either run at you or spit at you. Believe me, you want them to run at you.
My-Bullets-Can-Go-Round-Walls: these armoured aliens and their cheating ammunition make a return from the last game.

Yet again, this game doesn't let up and I struggled for every last inch I made it through. I also met up with some soldier friends who, for some reason, refuse to go any further and help me. And I refused to kill a scientist because (while they're still a bit pathetic) I just knew that he could later help Freeman with one of his life saving syringes. Oh, and because I'm a good person of course :).

Goodbye for now, Harry