Step up

https://m.youtube.com/watch?v=XkqLCNq7_2U

We have Hyundai and KIA to thank for small cheaper cars not being ugly sh** boxes anymore, all the other manufacturers had to step up there game to keep up.

Easy words but I’m not sure what they mean.
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The person is expressing an opinion about the impact of Hyundai and KIA, two Korean automotive manufacturers, on the smaller, less expensive car market. Prior to the entrance of these companies, the speaker seems to believe that smaller, cheaper cars were often less aesthetically pleasing or "ugly." However, when these companies began producing smaller cars that were both affordable and attractive, it forced other car manufacturers to improve their designs ("step up their game") in order to remain competitive.

In simple terms, the person believes that Hyundai and KIA should be credited for improving the design standards of small, affordable cars. Other car manufacturers had to enhance their designs to match the quality presented by these two companies.

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Very interesting. Even there’s a vulgar word is included, it actually conveys positive meaning.
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Yes, absolutely. Quite often, the use of colloquial language or slang can be instrumental in conveying a person's strong feelings towards a subject. In this case, the speaker is using a vulgar term to describe their negative impression of cheap cars prior to the impact of Hyundai and KIA. By using such strong language, they are emphasizing how the superior design aesthetics introduced by these companies have dramatically improved the market. Even though the language is crude, the overall sentiment is actually positive about the role of Hyundai and KIA in improving the quality of affordable cars.