My aswell share my horrible stats. Spoilers.
Big Square: 2:14:07
Loved the game, but just some small complaints.
Backtracking through the tower wasn't hard. At least it was much easier than getting up the tower. It wasn't really a surprise, I even was planning to backtrack anyway. I kinda realized this because as I was playing through my second time (my data got deleted at the last floor). So by the time I replayed it, I played as well as I would've played it both times as I already pretty much mastered the controls.
I wish the down NPC squares were more climatic as I backtracked unnecessary parts to find their dialog (which means my time would be even lower down the tower). I think one of the NPC square's dialog was copied. It was "Oh you killed Pineapple instead of Big Square? Oh no!". Or at least it was so generic that it wasn't worth the back track. I wish the tutorial npcs could be accessed with new dialog. That's about it.
Good things. Fun gameplay, the checkpoints were forgiving. Even though people complain that it is hard, it's forgiving enough to not make you play through many hard parts in a row just to master one of those hard parts. I liked the toxic sludge at the beginning, I wish the tower had more aesthetics like that though. The gameplay did not feel repetitive or tedious, as even though you used a few objects, the challenges faced seemed unique. It was funny too. I liked how I could destroy fellow turrets. From then on I vowed to destroy every turret. On my way down I spent quite a bit of time circling a turret trying to get it to shoot itself (more time lost).
To wrap it up, great game! Hope it gets better in ICE!