The art style is great. I can tell you really like the art! The game was short and sweet, which considering you pivoted in the last 2 days was a good idea. I found that the voiceovers when picking the objects to be a great way to add audio feedback for the player. Good job!
If I were to add to this
I would add the visual feedback I mentioned down below. Hopping penguins, particle effects, animations would add to the reward the player feels for feeding the penguins. I would see if I could increase the skill curve and add a couple more levels.
Game Design
I'm going to be using Jonas Tyroller's framework for fun for these reviews, so you can watch his video for more context around it.
Impact
I think the idea of building a bridge to allow penguins to cross is a great idea. Building the bridge provides progression and allows the player to impact the game.
One thing this game could be improved by is visual feedback for picking items, placing planks, and feeding penguins. Something like penguin reactions to being fed batteries, some particle effects on the bridge being built, or some animation on clicking the items up top would help with that.
Challenge
Challenge is one of those things that's different for every person, so it's pretty hard to get right. I think you did a good job with the starting challenge. It took me losing once or twice before I realized everything I had to do. A tutorial would help with that. Unfortunately, the skill ceiling wasn't much higher than the floor and once mastered, I didn't have an issue getting through the levels.
In terms of fairness, I think the game didn't have any sucker-punches that I wasn't expecting. That's always important that the player doesn't feel cheated.
Fantasy
I think fantasy is one of the most important aspects of a game. A great fantasy can hide a crap game, while a great game with no fantasy has a much harder time standing out.
For yours, I feel the fantasy is great! I love the idea of helping cute penguins trying to cross the water. The art style was consistent with the fantasy and the music and audio helped it come together as a light-hearted game.