Thank you for playing! We had a lot of fun creating it. Also, all of levels 1 and 2 are possible with just the dash and shotgun, because of the aforementioned kickback quirk — shoot really early in your jump and you’ll go flying! The secret rooms are unlockable if you complete the game and go back to the beginning, where you’ll now have all your abilities unlocked from the start! (And a secret extra one…)
(As for the softlock, that’s right around where you unlock the grappling hook, I believe. Keep falling through the semisolid platforms to grab the treasure, then a new path will open up for you!)