Hi! First of all. Thank you so much for playing!
You make a lot of good points. The first immediate tips I can give you is to use the options tab in the menu (Open it with the M key) and select difficulty, there should be an option to lower the damage Crania takes per hit. Also, the meat you collect needs to be used from the inventory as well. If the lizard starts spinning and doesn't stop, jump over him and press space again to do a stomp attack, It will hurt him, but won't kill him. A bit later in the mission you'll unlock the pheromones, which you can use to arouse those lizards instead of fighting them, making it much easier.
However. I'm effectively redesigning the whole game, mostly graphics, character design and to add more detailed level design. I do agree that forcing you to not hurt the lizards was a bad idea. So I'm making it more optional in the future.
The whole first mission in the desert will be changed, but I'm keeping some of the levels and will rework them as sidequests for the future versions.
I will consider adding jumping where the force of the jump depends on how you hold the jump button, but that one is tricky to add.
If the first tips help, I would love to hear more feedback from you. Thanks again for playing!