Half Life 1:
Favorite is Alien Grunts, they look cool and put up a fight, not to mention the inherent awesomeness of a gun THAT SHOOTS BEES. However, I agree on you with the ichtyosaur[sic], but mostly because they're so goddamn hard to fight! You can scarcely see them, they take more than a...
He uses regular Xenian portals, not a portal gun. Either way, it'd still be very difficult to traverse the facility with a portal gun, not to mention you can't clean them up manually.
Additionally, there are no pictures of Cave Johnson. HUUURRRRRR
Why are they being dehumanized? Personally I'd love to have enemies you can be sympathetic towards, so not only would the game itself pose a challenge, it would also present a moral issue.
To be honest, I'm disappointed. I never really had any fun in the game. I spent about an hour wandering around Mars City's ridiculously dark corridors, even before the accident. Then I FINALLY found the missing scientist.
I promptly wandered through an evironment that was even DARKER...