MySql cannot add foreign key

This is the code I have.

CREATE TABLE Users ( user_id int(11) NOT NULL AUTO_INCREMENT,

user_name varchar(30) NOT NULL,

password varchar(30) NOT NULL,

creation_date time NOT NULL,

badges int(11) NULL,

number_written_reviews int(11) NULL,

accountType enum('Reviewer','Admin'),

PRIMARY KEY (user_id)

)

CREATE TABLE Game ( game_id int(11) NOT NULL AUTO_INCREMENT,

  `game_image` MEDIUMBLOB  NOT NULL,

 `game_name` varchar(25) NOT NULL,

 `developer` varchar(25) NOT NULL,

  `genre` varchar(25) NOT NULL,

  `time_to_complete` time NOT NULL,

  `release_date` date NOT NULL,

  `avg_score` float NOT NULL,

  `description` varchar(300) NOT NULL,

  `review` varchar(150) NULL,

PRIMARY KEY (`game_id`)

)

CREATE TABLE Review( game_id int(11) NOT NULL,

`score` int(11) NOT NULL,

`review` varchar(150) NULL,

`user_name` varchar(30) NULL,

PRIMARY KEY (`game_id`)

)

ALTER TABLE Game ADD CONSTRAINT gameReview_fk1 FOREIGN KEY (review) REFERENCES Review (review) ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE Review ADD CONSTRAINT reviewGame_fk1 FOREIGN KEY (game_id) REFERENCES Game (game_id) ON DELETE CASCADE ON UPDATE CASCADE, ADD CONSTRAINT reviewUser_fk2 FOREIGN KEY (user_name) REFERENCES User (user_name) ON DELETE CASCADE ON UPDATE CASCADE;

Why can't I add the foreign key constraints?