NOTE: As their name suggests hints are not exactly Devil May Cry 4 cheats, and are usually just simple (but very useful) tips on how you can unlock secret level, features, find hidden areas and such. Hopefully these will make playing Devil May Cry 4 even more entertaining.
Achievements
Complete each achievement to get the allotted gamerscore.
A Comfortable Pace (10): Clear mission 11 in Human Mode.
A Cut Above (30): Clear all missions in Devil Hunter Mode with an S ranking.
Done and Done (20): Clear all missions in Devil Hunter Mode.
Easy Does It (10): Clear all missions in Human Mode.
Filled with Pride (10): Acquire 10,000 Proud Souls.
Half Way There (10): Clear mission 11 in Devil Hunter Mode.
River of Red (10): Acquire 10,000 Red Orbs.
Rookie Devil Hunter (10): Defeat a total of 100 enemies.
Simply Spectacular (10): Complete a mission with an S ranking.
Smokin' Sick Style!!! (10): Complete a Stylish Rank SSS (Smokin' Sick Style!!!) combo.
Smokin' Style!! (10): Complete a Stylish Rank SS (Smokin' Style!!) combo.
Smokin'! (10): Complete a Stylish Rank S (Smokin'!) combo.
The Best of the Rest (20): Clear all missions in Human Mode with an S ranking.
Complete Ending
After beating Devil May Cry 4 and viewing part of the ending, the credits roll. During this time you have to protect Kyrie from being hit or the credits will end prematurely.
See the rest of the ending: Protect Kyrie during the Credits for 90 seconds.
Unlockable artwork
Demon Invasion: Beat Dante Must Die mode
Light from the Demon Blade: Beat Hell or Hell mode
The Cast: Beat Devil Hunter mode
The Demons; 12 publicity pictures: Beat Son of Sparda mode
The Ladies of Devil May Cry: Beat Heaven or Hell mode
The Two Heroes; 29 character images: Beat Human or Devil Hunter mode
Unlockable difficulty levels
Dante Must Die mode: Beat Son of Sparda mode
Heaven or Hell mode: Beat Son of Sparda mode
Hell or Hell mode: Beat Dante Must Die mode
Son of Sparda mode: Beat Devil Hunter mode
Super Costumes
Super Dante: Beat Dante must Die mode
Super Nero: Beat Dante must Die mode
Bloody Palace
Unlock the Time Attack Mode, Bloody Palace: Complete the game on Devil Hunter difficulty
More Difficulty Levels
There are three "elite" difficulty levels that can be unlocked in the game. Once you've unlocked Son of Sparda mode, you can play through it. If you get through it, two more difficulty levels will be unlocked -- Dante Must Die and Heaven or Hell. If you get through either of those subsequent difficulty levels, you will unlock the final difficulty level -- Hell or Hell.
Free Health from Faults
Late in the game, you'll occasionally see fault enemies appear from underneath you--they sort of warp up from the ground and try to ensnare your character. If you manage to kill a fault, you will always be rewarded with a free health orb. If you're low on health, look for faults to kill and get their health.
Easy Orbs (Mission 3)
Here's a great way to collect a lot of orbs. After you finish the game's third mission, go back through and play it again. From the start, run past the statue into the first hall, where you can kill enemies to collect experience points and orbs. Then, seek out a hallway where a wooden wall stands. Break through the wall, where you can find a crystal. Break the crystal to collect an automatic 1,000 orbs. Then, exit the mission. This is a quick way you can repeat over and over again to collect as many orbs as you'd like (and some experience, too).
Here's another great method to get even more orbs on the third mission. The technique is similar enough in the beginning to the one above -- you'll want to seek out the same wooden wall that can be broken down. Kill the enemies there after breaking down the wall, then backtrack to the red crystal in the area. Hitting it with your sword will give you 850 orbs right off the bat. But if you power up (using Devil Trigger) and attack it, you'll get over 3,000 orbs! This only takes a couple of minutes to accomplish, and like the technique above, can be repeated at will.
Easy Orbs (Mission 7)
There's another easy way to get a lot of orbs, this time on the game's seventh mission. Better yet, it will only take about twenty seconds to get about 4,000 orbs. At the beginning of the mission, break the egg-like objects to your left. Then, head forward to a tunnel and break more of the same egg-like objects. Turn right at the end of the tunnel, and you'll see a gem. Execute a streak with the Exceed Gauge full, and then immediately use the Devil Trigger and combo it. When the gem finally breaks, you should have around 4,000 orbs. After that, all you have to do is retry the mission and do it over and over again as needed.
Control the Camera During Cutscenes
During any cutscene in the game, the camera can be controlled, giving you alternate views of what you're seeing. To move the camera around, use the right analog stick on your controller. You can zoom in and out by using the right trigger button.
Dice Game Exploit
Here's a great way to cheat at the boardgame in the Game Room. When you roll the dice, you can actually predict the number you will roll every time. The number showing on the die before it's rolled is the number that will show up if you count properly. So, for instance, if you would like to roll the number three, simply way for the "3" to show up on the top of the dice. Count six rotations before you strike the die, and you will have rolled a "3"! This is great for exploiting the game to win extra orbs.
Quasi-Secret Launch Jump
Either Nero or Dante can perform a launch jump off of ledges that sends them flying far forward, much further forward than a normal jump. This launch jump can be used to collect secrets and sometimes shortcut secret missions. To perform it, stand facing a nearby ledge that you can jump off of. Perform the Streak or Stinger attack (while locked up, press UP + Attack) and Nero or Dante will dash forward--the ledge cuts off the attack animation and instead launches the character far forward.