Easily Unlocking Hunk In Mercenaries:

First, go to the third level. This is where you can unlock Hunk to play as in The Mercenaries. If you have other characters, ignore them. Pick Leon.

This level is very easy. Every enemy will die with only two hits. An important thing in this level is not to use the knife, because it does not have that much power and it will waste time.

First, run around shooting every enemy twice. Only use the knife to occasionally break open barrels for ammo and healing items. Once you see a clock, do not hesitate to pick it up, and do not leave it for when you need it. Pick it up immediately. Eventually, the large men wielding the turrets will show up. Avoid them mostly, and only kill them when you have the advantage. Also, when you kill them, make sure there are no other enemies close. If you ever get crowded, use the riot gun you are given. Also, use the riot gun on the men with the turrets. Only use healing when you need it. Use green herbs first, and when you run out, use the first aid sprays, but only when one more hit will kill you, or if you are unsure that you will survive another hit. Don't forget to keep picking up the clocks, and drop from ledges and run in different directions to evade the wild fire of the turrets.

By the end, as long as you score at least 40,000 points, you will get a four-star rating. 60,000 points will get you a five-star rating.