Day 27 is going to BURN!
BUTT...
I think you’re gonna like it ;-)

Here are some pointers on how to keep your balance & stay in control of the runner’s lunges if you feel like you’re flailing all over the place [LOL]:

maintain a straight line from your head, down through your hips & all the way to your back foot, both as you’re stepping back & as you’re standing up.
yes, the movement is a hip hinge: booty back, head forward, spine straight ;-)
keep each foot in line with its respective hip. Careful not to let the foot that steps back move toward or cross over your midline because that will definitely throw you off balance!!
another way to put it: don’t stand “on a tight rope” [with your front foot directly in front of your back foot]. Your midline goes from your nose to your belly button & down *between* your feet. Your right foot should be on the right side of that line & your left foot on the left side.
on a similar note: keep your hips square. Neither hip should be higher than the other at the bottom of the lunge. If that means you shouldn’t reach all the way to the ground that’s ok!!
keep your abdominals tight & your lats engaged [pull your shoulders down & away from your ears] at all times!
drive through the heel of your front foot as you stand to engage your glute rather than stress your knee.
think about using your hamstring to pull your hips forward & back up over your feet/under your shoulders.
for the skip-ups especially, think about only moving upward as you step your feet together - crown of your head right up to the sky! - because moving forward is going to throw you off balance.