I really liked the idea and main mechanic of the game; however, the game was too hard for me to be able to enjoy it properly. As Bobo_Baqa said, the game is too fast to be able to react properly, the randomness results in some impossible scenarios (I once started and the first zone had 5 oxygen and that's it, another time I had both type of walls on top of each other and when I tried to break one it touched the other and ate my bullet), and some element spawned too close to be able to properly grab the one that you really want (especially when you're almost full and can only grab one). In addition to that, on my side the aiming wasn't where my mouse was: I had to pull my mouse down for it to shoot straight. Instead of emptying the whole inventory, I would've liked to be able to select which atom to drop instead, because sometimes you accidently grab the wrong atom and you have to empty everything and won't have enough to break the next wall.
Overall, the game was clear and easy to understand with an very interesting mechanic, but needed a few balances to reach its full potential, as expected from a game jam. A good effort nonetheless :)