As of 20240404 (zig version 0.12.0-dev.3562+96bc8f17c), Zig provides one of the best possible semantics to optimize memory details, while offering widely portable source code with reasonable safety in a relative concise and readable way.

Aside of signaling for toolings, I found personally no major annoying parts.
For example, picking up nested slices and some build system parts might be inconvenient, but those are one time things and no footguns.
The rest of the language feels very smooth to me in contrast to the potential very flexible and cryptic syntax of C (see preprocessor iceberg).

• Bottlenecks of array assignments not obvious via @memcpy.
  

  test "perf array assignment" {
      const x: u8 = 100;
      const x: [1_000_000]u8 = .{x} ** 1_000_000;
      var b: [1_000_000]u8 = undefined;
      // pile of code
  
      b = a; // spot the performance issue
  
      // pile of code
  }

• Signaling: Test runner allows no signaling to qemu -g 4242 (debugger mode). Qemu uses gdb server signaling, which means sending SIGKILL is necessary to kill the debugging server process.