If you want a different creature/egg/NPC creatures, download this project and modify it yourself! Spore creatures are represented as PNG files. Click your egg to make it hatch. Once clicked, an exam appears, asking you to fill out all your creature statistics (if you have Dark Injection parts that enable higher levels or if your creature has captain parts, simply give it 5). Once your egg hatches, you can give it a name! Also, the answers in your examination do matter to gameplay. Press J, G, C/0, S, or W to (respectively) jump, glide, activate/deactivate camouflage, sprint, or walk to an area. However, you can only do these certain actions if the creature is capable of doing so (proved from the exam). You can also hunt down creatures. Press 1, 2, 3, or 4 to respectively Bite, Charge, Strike, or Spit Poison at the creature. If you Charge or Launch Poison, the creature/poison will follow your mouse. If you want them targeted to something, mouse the creature/poison to that target. Also, attack levels do depend on damage and effects to the target. Once your prey is dead, you can move your creature to the corpse, press E and eat it (ONLY if you are a carnivore/omnivore). This process takes about 5 seconds. If you are herbivorous/omnivorous, you can eat fruit seen at the bottom-right corner of the screen. Press "F" to change its appearance. Fish can be eaten by carnivores/omnivores only. Eggs apply to all creatures. Only press E when your creature is over it to eat it. You can also battle an opponent! Just fight him the exact way you'd fight prey. You can also press D to temporarily dodge attacks. Enjoy
This did take quite a while to make. You can have your own pet Spore creature! Just go inside the project and modify the creature PNGs and egg style/design to your desire. You can name your pet, feed him/her, battle with other creature opponents, play around with abilities, and hunt down other creatures! Enjoy! I'll fix glitches time to time when I find them, so don't worry.