Really polished stuff and having a laugh within the first few seconds is always a good sign (the sheep dropping from the sky). Everything was intuitive and looked great. I only have tiny nitpicks as the game flowed perfectly: maybe a visual indication that a sheep is equipped with a parachute and a faster/fastest option like the original Lemmings...
Oh and I guess the cruelty option that always made me feel bad: the 'mushroom cloud icon', lol. I'm glad you didn't make the levels absurdly difficult like Lemmings 2 though I'd loved to have seen a couple more levels (and I don't usually say that on gamejam games)
...also couldn't help but make a dog tower of babel on level 5 :)