The 4-up playback is the major feature and works well. Still, there are simple controls that we expect in all MacOS applications that are missing here. Wanna switch from 1x playback to 0.5x playback? You hafta click through 2x, 3x, 4x, 8x, 16x, then once more to 0.5x. A better control is necessary. How about key press shortcuts for these speeds (as in other video players? How about key press shortcuts for jump-back-10-seconds, jump-forward, and pause/play? How about a wider control for the playhead so that scubbing the video is easier and more precise? In short, look at the best desktop video players that allow convenient and useful control of playback, and copy those features. Also, when opening a clip, the resulting window always opens in the same place at the same size. If a user adjusts that size, how about having the next clip open with the same position and dimensions instead of making the user reposition the window with each clip? Also, I haven't figured out yet how to delete lots of clips all at once. There doesn't seem to be a way to select multiple clips so that a single delete command will do the trick.