It's tempting to compare this to the iconic 1978 film, and there are some areas where comparison isn't just inevitable, but unavoidable. However, holding this to the same level of expectation as the film isn't entirely fair.
Firstly, it's a TV movie, not a theatrical release. And it couldn't be more obvious. This is a stripped-down Grease, a little more complicated technically than a Broadway stage performance, but not to the scope of anything that came before it. It has a "budget" feel to it from start to finish, which doesn't make it inherently bad. What could've been a production that thrived on the spontaneity of a live performance ultimately suffers greatly as a result of its reductions. The acting is on par with television acting - good enough to do the job, but with a great deal of room for improvements and enhancements. Try though they may, this fails to live up to the energy level that one likely has come to expect from a production of Grease as well. The dance moves are all there, but they just don't feel the same.
The biggest reduction of the film was the inclusion of modern music, noticeably DNCE's Cake By the Ocean which, although performed in a style more reminiscent of the time, is quite jarring. A modern-day pop song just doesn't sit well in a period piece from multiple decades ago, no matter how you slice it.
The old favorites are done rather well. There was no skimping out on the production value of the music itself. There are modifications for TV, but some of the lyrics ignore the modifications made for the film in favor of the Broadway show which, despite being a fan of the movie, was a nice change.
It was really interestingly staged to give the mirage of a Broadway show as well, which added to the charm of the project as a whole.
Overall, it wasn't too bad. No something I would be particularly eager to go back and revisit anytime soon, but good enough to be a satisfying experience. Grease is STILL the word!