- no threads (isolates are much more limited)

- no value types

- missing fundamental integer types (eg. 64 bit unsigned integer)

- no data classes (records are anonymous)

- no tagged unions

- no static metaprogramming (macros coming soon)

- limited constructors (initializer list expression can't use earlier values in the list, no object initializers)

List<int> is still too often used in APIs instead of Uint8List, even though it has 8x overhead.

Slower than C#, Java, Kotlin & Go. Performance is same as JS (even though it's statically-typed, AOT compiled language).