This review might be a bit mis-informed, considering I've never owned a fighting game other then a few early Street Fighter games, which I didn't play much. That being said, I really love this game. It's just enjoyable.
I'd say this is a very good game for beginners to the genre. The tutorials that come with the game are just fantastic. There are 16 tutorials plus one for each individual character. These tutorials will teach you what mix-ups are, what "Hit confirming" is, how to punish opponents, etc, while the character-specific tutorials teach you all the moves of the character and how to use them. There's plenty of information here that'll be very useful to beginners.
There are 2 different single player modes, multiplayer lobbies and quick matches, and a training room for you to mess around with.
The two single player modes include story and arcade.
There is a different story for each character. Story mode follows your character and their mission to get the "Skull Heart", something that will give you one wish in exchange for becoming the "Skullgirl", who is basically evil. Story consists of a bit of text, then a couple matches, then more text, then a boss, and ocassionally another match after the boss. I don't know how long story modes usually are in fighting games, but I wish these were a little longer. You don't fight every character in the roster in these story modes, only a few. The boss isn't too enjoyable, for me; she uses lots of cheap tactics and isn't really a "Fight", as I always find myself spamming one attack until she dies, because you can't use any combos. I would've much prefered a normal fight but with a stronger enemy. The little stories the characters go through are quite interesting sometimes. I liked learning the backstories of my favorite characters like Squigly and Painwheel, although with other characters you don't get too much information about them.
Arcade mode is a randomly generated challenge where you fight lots of different characters in different numbers (You can have up to 3 people on your team, which I'll get to later), and it is more fun then the 1v1 fights you get in story mode. This mode is also a lot longer then a character's story mode because any 1v1 fights have 2 rounds. At the end of Arcade you fight the boss from story mode. Something I really liked about arcade is that even if you don't have the DLC characters, you can still fight them. This lets you see if you like the way one looks, and this led me to buying Squigly instead of Big Band.
There are 6 difficulty settings, from Sleepwalk to Nightmare. Nightmare isn't as hard as I'd like it to be, although it makes the final boss unfair, and a really frustrating difficulty spike.
Training is where you'll try out different combos and characters and things. Not quite sure, again, how this holds up to other fighting games, but I liked the different options I could switch on and off to help me practice, including hitboxes, icons that show you what you are pressing, grids, hitstun bars, slow-motion, recording, and settings like how much meter you start with, among other things.
Something I really felt was missing from Single Player was a straight up single match mode. Sometimes I want to try out certain strategies against certain characters without having to do story or arcade. This would've been nice but it isn't too major of a problem I have with the game.
I don't know much about the multiplayer modes considering I haven't ventured there yet, except for fighting my friends.
There's a tournament mode, ranked play, lobbies, and local play.
Local play is playing with someone you're physically next to on the same computer. For this you'll need another controller for the other person to play with.
Lobbies is where you'll usually go when you want to play with a friend from different computers, or play unranked. Then, of course, there is standard ranked play, which I haven't gotten into, so I can't tell you too much about it.
As of now there are eight characters, two of which are locked in story mode in the beginning, 3 DLC characters, with two more confirmed, and 1 secret character, who is selected by going to the tile underneath Double. This is considered a small roster to my knowledge, but I found this a plus in my opinion, being new to fighting games. It allowed me to focus more on one character.
All of the characters have different playstyles, though. Each one feels unique.
The artstyle of this game is very nice. The backgrounds for each stage are beautiful, the soundtrack is mostly jazz and is enjoyable to listen to, and the characters all look very interesting and different.
The only character design I found underwhelming was Parasoul. She always looked kind of plain to me, near other characters.
There is also an art gallery if you like collecting everything.
Fighting is very fluent in this game, in my opinion. It always feels rewarding to hit someone and pull off comboes.
Each character has 3 punches and 3 kicks, with crouching, jumping, and sometimes forward/back variations to these, along with an array of special moves. Characters also have at least one grab, and their own Blockbuster attacks. Blockbuster attacks use meter that builds up after hitting opponents or being hit. Blockbusters use 1 to 5 meter, 5 being the limit.
There's also an anti-infinite combo system you can use to break out of infinite comboes. You can break out of an opponent's combo after they have repeated a sequence of attacks in a combo twice.
You can have up to 3 fighters in one match you can tag to and use assists from. The more characters you have, the weaker they get, so you're more evenly matched fighting 1 character with 3. This is nice if you want to practice with just one character, or if you don't want to juggle 3 at a time.
Overall I'd really recommend this game. It's great to play with your friends, online, or even alone. I definitely think it is worth its money, considering it's a ton of fun, there's lots to play to last you a while, and that there are more characters on the way. Definitely pick this up.