I'm gonna make things really simple here and just say that if you don't know about t-spins and making squares out of tetrominos, then you probably won't get as much out of this game as I do. The thing with this version of Tetris is that it has a few mechanics in it that allow you to clear more than 4 lines at once, and increase the value of single lines. There's no "points" score, like most Tetris games, instead the game counts up your lines cleared and then after a game over will add that to a total line count for your profile. The line count contributes to unlocking new ancient structures, which is completely pointless, so you can just ignore that pretty easily.
The different game modes are there, I guess, but my personal opinion is that you really only wanna be there for marathon, since it lets you just keep playing and there are better Tetris games out there for PvP Tetris action. What you really wanna play this Tetris for, though, is the soundtrack and handling. The soundtrack is based off of different cultures and locations in the world, so you've got a really great variety of sounds and genres to go with your Tetris fun times. The handling is pretty good, and easily comparable to other Tetris titles from around the time of this game's release.
I mentioned the advanced mechanics earlier, so I'll actually explain. This is the first time I've seen two specific mechanics in a Tetris game.
Those mechanics would be Square and Cascade, which are both in Tetris worlds, but only as separate game modes. This one has both of those rules applied by default. To use the square mechanic, you have to make a perfect 4x4 square, using 4 complete tetrominos. You'll create a silver square with different pieces, and a gold square with a square made out of 4 of the same piece. This mechanic is worthwhile and relevant because a line with a gold square in it is worth more than a single line with normal blocks. Cascade is an important mechanic which makes every piece separate into individual blocks which will then fall, allowing you to get line clears which are worth more than a Tetris. The tricky part of cascade is that you need to use t-spins to activate it. Depending on which t-spin you use, you'll either cascade every block above your piece, or every piece above and below. These mechanics together make it fun to just mess around with this game, so it gets really easy to get sucked in. If you're the type to get into the mechanics and systems of individual Tetris games, you might find yourself spending hours pointlessly prodding at this game.
The long and short of this, though, is that this is a Tetris with not a lot of structure, but a lot of mechanical substance and having the game keep track of all your lines makes it feel good to get a really good round and throw another 400 lines onto your line count. I recommend this, and maybe some of you might learn some new Tetris tech you might have missed, if you're a more casual Tetris fan.
I'm gonna make things really simple here and just say that if you don't know about t-spins and making squares out of tetrominos, then you probably won't get as much out of this game as I do. The thing with this version of Tetris is that it has a few mechanics in it that allow you to clear more than 4 lines at once, and increase the value of single lines. There's no "points" score, like most Tetris games, instead the game counts up your lines cleared and then after a game over will add that to a total line count for your profile. The line count contributes to unlocking new ancient structures, which is completely pointless, so you can just ignore that pretty easily.
The different game modes are there, I guess, but my personal opinion is that you really only wanna be there for marathon, since it lets you just keep playing and there are better Tetris games out there for PvP Tetris action. What you really wanna play this Tetris for, though, is the soundtrack and handling. The soundtrack is based off of different cultures and locations in the world, so you've got a really great variety of sounds and genres to go with your Tetris fun times. The handling is pretty good, and easily comparable to other Tetris titles from around the time of this game's release.
I mentioned the advanced mechanics earlier, so I'll actually explain. This is the first time I've seen two specific mechanics in a Tetris game.
Those mechanics would be Square and Cascade, which are both in Tetris worlds, but only as separate game modes. This one has both of those rules applied by default. To use the square mechanic, you have to make a perfect 4x4 square, using 4 complete tetrominos. You'll create a silver square with different pieces, and a gold square with a square made out of 4 of the same piece. This mechanic is worthwhile and relevant because a line with a gold square in it is worth more than a single line with normal blocks. Cascade is an important mechanic which makes every piece separate into individual blocks which will then fall, allowing you to get line clears which are worth more than a Tetris. The tricky part of cascade is that you need to use t-spins to activate it. Depending on which t-spin you use, you'll either cascade every block above your piece, or every piece above and below. These mechanics together make it fun to just mess around with this game, so it gets really easy to get sucked in. If you're the type to get into the mechanics and systems of individual Tetris games, you might find yourself spending hours pointlessly prodding at this game.
The long and short of this, though, is that this is a Tetris with not a lot of structure, but a lot of mechanical substance and having the game keep track of all your lines makes it feel good to get a really good round and throw another 400 lines onto your line count. I recommend this, and maybe some of you might learn some new Tetris tech you might have missed, if you're a more casual Tetris fan. 
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