A look at monster hunters new features and my opinions thus far.

User Rating: 10 | Monster Hunter 4 3DS
I've reached the point in monster hunter 4 where all the features are unlocked and i feel i can give an accurate review of the game i'll continue to play for some time to come. (Put in about 40 hours i think)

I should note that this is the Japanese version of the game. I dunno how it'll vary from the western release.

Also if you want a TLDR, the game is amazing, my favourite Monster hunter to date. I am having trouble finding time to play GTA5 because this has already sucked me in.

Now i picked up monster hunter 4 on release day, I played MH1 and the MH3s, so i'm pretty familiar with how things work and their typical game play.
When it comes to this, most of the game plays out as the others did. You'll get various missions and hunt big monsters for their body parts which you'll turn into armor and weapons. If you haven't played a MH game until now, this probably doesn't sound as addictive as it is.
However, frankly, it's a great time. I have no idea why, sometimes i hate grinding monsters for that one rare body part (one took me 20 kills to get), but when you finally get that part and make your new gear, you just want to go and do it all over again. That said, i never found the grind to be anything but fun. Sure, it's frustrating to not get the drop you need, but the fights remain fun. This game is never really boring. The times i was sick of fighting that one monster, i could find another and come back to it later.

Anyway that's the general formula. Here are the things that are different.

Firstly, there's a bit more of a story this time. It's not that great, but it kinda gives you something else to make you feel like you're progressing rather than just fighting boss battle after boss battle. (not that i don't love that fact)
The cast of characters aren't that well developed, but they feel like characters instead of just the dialogue dispensers in the other game. I wouldn't care if they had this or not, but it's quite nice i guess.

Climbing and terrain has been greatly improved.
I didn't know how this was going to work leading up to release. But i am happy to say that i really adore this feature. You can now fight monsters on several layers of terrain, climb cliffs to avoid assault, jump off ledges onto enemy monsters and latch on as you cut away trying to knock them over. The way all this works is pretty basic, but it adds a new level of strategy to combat. I find myself always considering my surroundings and fighting based on the area i am in. It's not THAT far from the old familiar formula (that they really couldnt change without upsetting fans), but it's enough to make our fights way more exciting.

Swimming is gonnnneeee
I know some people loved it. But i wasn't one of them. I used to dread water missions and considered them the major downfall to MH3G(Ultimate).
Having them gone is amazing, I consider this a huge improvement.

New monsters, missions and gear.
Doesn't really need to be said, but there are a variety of new monsters. Some of which already share a spot amongst my favs. They put a lot of thought into these monsters and each fight plays out differently. This is a vast improvement on some of the generic monsters who seemed too similar to others.
Another thing i've noticed is there are a hell of a lot more missions that have you fighting two monsters at once. You might have to fight a Rathian and a Rathalos at once. Or in some cases the two monsters can even work together to unlock unique moves and encounters that would be impossible on their own. This is an interesting concept and can make for some really challenging missions.

The difficulty i felt was pretty good. It's hard enough without being too punishing (provided you keep up with your gear) but not easy by any stretch of the word. The boss monster also feels very much like a boss.

Outside mission activities.
In MH4 you have your own personal cat companion. (you get to create it at the beginning with your character)
This is a sweet feature, i really enjoyed having a unique companion. As the game progresses you'll also meet other cats who you can recruit to help you. These cats will get sent out on missions by you to retrieve items which you can use to buy armor for your companion. I love how this feature works, it requires some strategy to get the maximum yield, but isn't complex at all.
Outside of this, you can get your cat army to help you fish in bulk, or even catch water wyverns.
A lot of similar merchants appear also. The basic ones aside, you've got people to trade items with and scout items for you.
You also have someone who can identify items you find in the world and upgrade them. These items cannot be modified by the regular blacksmiths. I should note that i am not 100% on the finer details of this feature as i am yet to find a piece of gear i wanted to use.
Oh and there are also character missions. People in town will send you out to complete a task for them and this may lead to other missions or upgrades to shops etc.

There are two new weapon types, but i haven't really used them much. There are now a plethora of different ways you can play, with so many different weapons. None of them play out the same, so find what you like.

Lastly i just want to say that the game looks and sounds amazing.
The only bad thing i could say about the entire game is that some particular areas look a little bland. (This is really rare and the only bad thing i can say)
And i still hate carrying eggs back in single player missions (this is actually quite uncommon and not necessary to complete thank goodness)
I think that's the gyst of it. Hopefully that shines some light onto things for those of you who haven't had the chance to look further into it because of a language barrier.

This is greatly improved, fun, addictive and value for money. I recommend this game to any Monster hunter fan, or anyone who likes decent boss fights. I'd go as far as to say this might appeal to those who liked the combat in Dark/demons souls as well.