I personally think playing the specific patterns you're having trouble with can do wonders.
But I also agree with Drace, it is important that you play entire songs with a large variety because you need to be exposed to different things and variations and combinations thereof. And it is a lot more fun.
Practicing one specific pattern you're having trouble with, can really help you get better at that pattern a lot faster in my experience. But just be sure that you play more songs than you practice specific patterns because mania is still a rhythm game after all.
Also this 'lvl' is just something mappers use to indicate how difficult they think their chart is. There are different standards though, but most will use the o2jam lvl standards (1-50, there are also levels beyond that but they are usually a bit on a weird scale imo. A lvl50 song can be just as hard as a lvl90 etc)
But I also agree with Drace, it is important that you play entire songs with a large variety because you need to be exposed to different things and variations and combinations thereof. And it is a lot more fun.
Practicing one specific pattern you're having trouble with, can really help you get better at that pattern a lot faster in my experience. But just be sure that you play more songs than you practice specific patterns because mania is still a rhythm game after all.
Also this 'lvl' is just something mappers use to indicate how difficult they think their chart is. There are different standards though, but most will use the o2jam lvl standards (1-50, there are also levels beyond that but they are usually a bit on a weird scale imo. A lvl50 song can be just as hard as a lvl90 etc)