Has potential but there are some major issues taking the fun out of it.
UI drop actions need to await the mouse up event to be bearable. Clicking an action button could put it in the next free slot in the queue. Keyboard buttons too, Then your players can focus on the actual game instead of struggling with the UI. :)
It's kind of an unusual touch on the concept to let the player run part of a sequence and start the next sequence from the end point. I'm sure there could be some cool puzzle level ideas that takes advantage of that mechanic. Similar games i think often require you to plan the whole sequence in 1 go. The option/requirement to pause at at specific spot to be able to solve the puzzle on the next iteration could be a nice extra dimension.