I don't know what to say. Your combos seems almost perfect to me as they're well chained and everything, the combo with the black and grey stickfigures lacks power in the black figure's hits. It seems as though you haven't given the kick enough anticipation nor the poses allowed any of it. What I would do to fix it is to use the same amount of frames but tweak the poses a little bit so as to give the leg enough room to wind up for a powerful enough kick. Basically give it some extra range, if it makes sense. It should be useful to make the spacing heavier as well. Same thing kinda goes for the rest of the combo, and the rest would be just nitpicking. It's good.
The one with the orange stickfigure, if I saw it on the anonymous section, I wouldn't have helped but think it was Firecracker's for how similar it is in terms of style. Though, I would change the last keypose to something like this, for example:
Seems like you were struggling with finding a way to transition to that upper cut without breaking your arc or spacing in general. To avoid this situation, try not to think so much about your arcs and just create your keypose th way you want it to be the add inbetweens. That will clarify it for you. Last pose is importat because it adds to the overall appeal of the whole animation, so pay attention to it next time. It's still neat to see you finishing the movements to the very end which is something many tend not to do, so kudos to you for that.
Over all, your combos are so good, now I would suggest you move to something else. Try to explore new things. Keep it up.