Well to be fair, your system is good as it is and better than most games in the jam. So its more of a nitpicking for details. I replayed your game to feel the movement again and I can not see any input buffering for fast button presses. Held buttons work fine, but does not really accommodate for a second button pressed during the movement. I got a fairly working system for my game last year so this year I just reused it. But still some players still find it confusing... If you plan to enhance your movement system you can just do it before the next jam.