Easily my favourite Lego DC DtV movie (I've seen them all). The makers are doing a grand job of expanding their universe; as well as the usual Lego Justice League, here we get Atom, Firestorm, Zatanna, Dr Fate, Plastic Man, and B'dg. Plus Reverse Flash, Krypto, and Ace the Bat-hound!
Incidentally, it's interesting that despite featuring the League prominently, this is only the second Lego DC DtV to have been released under a single character's name (the first was Lego Batman: The Movie - DC Super Heroes Unite back in 2013); the rest have all been released as JL movies (even the Flashpoint DCUAOM was released as Justice League: The Flashpoint Paradox). That's possibly a result of the poor reception of the live-action JL and a desire to get audiences more used to the Flash as a solo brand ready for his live-action solo movie.
Anyhow, as usual there are various nods to DC lore tucked away for the finding. Much as I love the 'serious', darker toned DC comics/films, it's perfectly possible to enjoy these movies too. If you like the Lego DC movies I wholeheartedly recommend this one. Easily 9/10