The good parts:
-4 skills adding more depth to the gameplay
-Regular mobs are designed to be a treat rather than fodder.
-You can fight bosses at any fight in any difficulty from your house
-Chips acting like equipment, can have 3 at most and they all offer bonuses.
The bad parts:
-No stages, just small rooms where you fight some mobs over and over until you can fight the boss
-Only 1 weapon
-No punches/kicks to build dizzy
-No skill chip variety
-Chips tied to Cooldown which means just spam them when you can
-Most bosses can be stunlocked by chips, the only alternative is shadowstep spamming like the other games except shadowstep is much less safe now.
-Regular mobs are a bigger threat but also feel really, really spongy and annoying at most times.
-No multiple wrestling moves
-5 difficulties and all they do is make mobs tankier and do more damage(apparently the game is balanced around the 2nd or 3rd easiest difficulty, go Suda).
-Everything about the overworld is a chore
-Having to do a stupid mingame everytime you find a new save point
-Overworld has nothing but some collectibles
-Collectibles also don't offer you anything worthwhile
-Minigames don't offer you anything worthwhile
-Craft system where you have to fight bosses over and over for drops(including stuff like rare 5% droprates on the highest setting)
Then there's also a million things to complain in regards of plot, direction, music, etc. There's some fun to be had with this game but I'll be lying if I said it isn't a disappointment ever for people with low expectations and no matter how much someone likes it, NMH3 is an objectively bad product(overworld framerate is terrible, animations clip everywhere, audio goes out of sync with subtitles, bugs, bugs, bugs).