Sadly, left-handed is severely limited.

I’m not sure if it’s a limitation of the App Store’s permissions, but the left handed use leaves out the mirroring of the apostrophe and backspace keys. This means for left handed use, I would need to reach over to the right side of the keyboard to delete something, which is pretty significant especially while learning, as you’ll undoubtably make a lot of mistakes starting out. And even if you get good enough to make very little mistakes, the apostrophe key is still out of the picture.

Nonukez about Mirror-QWERTY: One-Hand Typing, v1.3