Cosmic Crush is described as 'Absorb smaller planets. Avoid larger ones. Watch out for gravity!'. There are more than 25 games similar to Cosmic Crush for a variety of platforms, including Online / Web-based, Android, iPhone, iPad and Android Tablet. The best alternative is Agar.io, which is free. Other Cosmic Crush like games are Slither.io (Freemium), Osmos (Paid), Thrive (Free, Open Source) and Diep.io (Free).
Fight other flowers for garden dominance. Florr.io is an online game produced by Zeach. It contains a rectangular map (garden) of increasing difficulty and enemies that you can fight to get special types of "petals".