Following are the items you can unlock in Resident Evil: The Mercenaries 3D, each with brief description of how you can unlock that item in the game. They are pretty self explanatory, so I don’t think you will have any trouble unlocking these.
How to Unlock All Characters
You will have access to three characters at the start of the game. In order to unlock the rest of the characters, you will need to complete different missions with specified ranks.
You have him by default.
You have her by default.
Clear Mission 2-3 with a B-rank.
Clear Mission 1-3 with a B-rank.
You have him unlocked by default.
Clear Mission 4-5 with a B-rank.
Clear Mission 3-5 with a B-rank.
Clear Mission 5-5 with a B rank.
How to Unlock Alternate Costumes
Every character has an alternate costume that you can unlock. In order to unlock this alternate costume, you need to complete the specified tasks.
Mission Level 1-3 get an SS-rank, or get 10 Medals.
Resident Evil 3 costume
Get an S-rank on Mission Level 3-5.
Get all S-rank on all Mission Level (except Level Ex).
Obtain 25 Medals.
Get all A-rank on all Mission Level (except Level Ex).
Obtain 20 Medals.
Get S-rank on Mission Level 5-5.
Get a B-rank or above for all Mission (including EX).
Resident Evil The Mercenaries 3D Medals
You require medals for several unlockables in Resident Evil: The Mercenaries 3D. Medals provide in some cases an alternate route to unlock an item, be it characters, or costumes.
Clear all Mission Level 1.
Clear all Mission Level 2.
Clear all Mission Level 3.
Clear all Mission Level 4.
Clear all Mission Level 5.
Clear all Mission Level Ex.
Clear all missions with an A-rank.
Clear all missions with an SS-rank.
Complete a mission with a partner.
Clear any SS rank mission with a partner.
Me, I Prefer Guns
Kill all enemies by gunshot on any mission above level 4.
Can’t Touch This
Clear Mission Level 4 or higher with no damage.
Clear Mission Level 4 or higher with 50 combo.
Clear Mission Level 4 or higher with 100 combo.
Defeat all enemies in a mission with a combo.
How To Kill
Survival Mission 10 waves cleared.
Survival Mission 15 waves cleared.
Unlock all skills.
Upgrade all skills to max.
One (Thousand) Down…
Defeat 1000 enemy.
Platoon of Two
Perform five melee attacks in a row during one turn.
Kill 3 enemies with a Grenade.
Chariot of Fire
Carry the game in sleep mode over 50 Km.
Like a Phoenix
Recover from Dying status 50 times in Single player.
Perform 30 taunts near enemy.
Shoot down item threw by enemies 20 times
Defeat 53594 enemies.
Master of Unlocking
Unlock all characters.
Dressed to Kill
Unlock all costumes.
Chicken Hunter Portable
Shoot a chicken.
Let’s Work Together
Play a Multi player game.
Jack of All Trades
Use all characters.
Leave No Stone Unturned
Play all maps.
Me, I Prefer Fists
Beat your enemy in hand-to-hand combat.
Defeat a Parasite with a Flash Grenade.
Head shot 100 times.
Clear a mission without missing a shot.
The Old Banana Trick
Walk close to enemy and attack.
Saw What You Did There
Set off proximity bomb by shooting it.
Opening a Dojo
Use all hand-to-hand combat of any character.
The Wesker Special r
Drop an enemy into megma.
Shoot down dynamite from an enemy and blow it in the process.
Strike from Behind
Attack an Executioner’s weak point at his back.
A Friend in Need
Save an ally from Dying status in Multi player game.
Clear a Mission Level 4 or higher with single weapon.
In the Buff
Clear a Rank A mission without using any skills.
No Turning Back
Clear mission without using quick turn.
No Guts, No Glory
Continue 30 times.
Play Duo Mode 50 times.
Resident Evil The Mercenaries 3D Weapons
You need to clear every mission with SS Rank using a character if you want to access all of that character’s weapons with all characters in the game. Alternatively you can spend 10 Nintendo 3DS Play Coins to unlock all the weapons of your chosen character.