Free soda, high degree of freedom, nice boss, snacks and drinks are provided, you are in control, high sense of accomplishment, and you can learn many things
You may gain weight, overtime is required under the responsibility system, no overtime pay, you need to know how to do many things, and there may be situations where the work never gets finished
You can be forced to work more than an extra hour every day, and you won't be paid overtime. They completely disregard the Labor Standards Act.
The boss especially loves emotional blackmail.
Run away fast.