Any advice on unlocking the costumes/getting A rank? From dabbling in the stages(got a B on all three), Steel Beast seems best. I'm aiming for Sherry's, which seems like no easy task. She only gets 9MM ammo.
And are any of the DLC stages worth it?
1) Learn item placements on the map, there are at least 3 green herbs and 1 red on every stage.
2) Depending on the map and your skill as you get more experienced, you will vary your strategy (collect everything first? or collect as you kill?). But a good starting point to learn any map just just collect everything before you start to kill.
3) If you're just aiming to unlock stuff first, don't worry if you've dropped the combo. Just stay alive and kill as many as you can. The score requirement for S rank is actually pretty low.
4) Find the most efficient way to kill each type of creature, preferably with a melee for the time bonus. Zombies can be killed by a lot of characters with just a counter. Javo's are best killed with a coup de grace for a beginner.
5) How to get a coup de grace on Javo: easiest method is a quickshot followed by a slide (or unarmed punch as Jake). A cheaper method is a headshot stun followed by a slide.
6) Not all characters are equal, in general alternate Chris is best against zombies while Jake is best for Javo.
If you're as addicted to mercs as most of us were, the maps are definitely worth it.