Some other differences between SMTIV and the other entries is that there is no defense stat, so you need to be more on top of your gear and party elemental strengths and weaknesses to mitigate damage cause even early level demons can wipe out a high level party if you are unlucky. On the brightside this applies to enemies as well so battles are pretty fast in this game and never quite drag like other entries.

There is also a mechanic called Smirk which is granted sometimes when you either exploit an enemy weakness or dodge an attack. Smirk only last one round but it will greatly boost your next skill used in battle and grants you 100% evasion making you immune to getting attacked. Though to warn you, enemies can use this feature as well so be careful.

When you fuse two demons together you are now able to choose which skills the new demon will inherent from it's parents. This is as broken as it sounds which is why SMTIV:Apocalypse and P5 modified it to be less game breaking.

Your main character can learn skills and magic, something you can do in Nocturne as well but the rules are different. When a demon completes all the skills it can naturally learn it has the ability to do Demon Whisper which allows the MC to learn one skill from the demon. If the demon teaches you a skill you already know, the skill gets a power boost up to about seven times if memory serves me correct, effectively making the MC one of the most powerful fighters on your team.

While your MC follows rules from previous games where his elemental strengths and weaknesses are determined by his equipment, new to the series is that the armor actually changes his appearance which can be fun to play around with.

Also if you die, you get sent to meet Charon who will bargain with you and let you go back and redo the fight for a price. You can either use in-game money or those Mii Coins used for the Mii minigames to bribe him.

Overall, SMTIV is designed to be a lot more user friendly than the rest of the SMT mainline games with the exception of the game's map being a bit complicated and easy to get lost in. For the most part, the game starts off pretty challenging but eases up once you get to Tokyo, at which point you should have a good grasp of the games mechanics.