Resident Evil 2

First - start a game with Leon Scenario A and beat it. Do as well as you can (get an 'A' rank to be sure, though i've read of people who have beaten it with a 'B' rank) and then play the reverse Scenario B game with Claire and repeat once again. Mind the time as well. Its easy to complete around the 2 hour mark which is what you should be aiming for when attempting to unlock Hunk.

I believe that you must beat both characters' scenarios with an A rank. Keep in mind that you can only get HUNK on Normal difficulty. The qualifications for the A rank are as follows:
-You cannot have more than three saves
-The game must be beaten within two and a half hours
-No first-aid can be used
-There can be no use of bonus weapons (Rocket Launcher, Gatling Gun, or Sub-Machine Gun)
Remember: The last qualification only applies to weapons you UNLOCK. You can still use the RL you get at the end and not have it decrease your rank. I think the same applies to the SMGs, but I can't speak from experience.
If your having a hard time with this, I would recommend using the infinite ammo cheat. That does NOT decrease your rank.