Most of the actual gameplay in E.V.O. isn't all that hard... but then you come to the bosses, and they're way bigger, stronger, and more maneuverable than you, which hardly seems fair.

But you have one weapon on your side, your Evo menu.

If you're low on health, pop it open

And choose anything, like changing the length of your neck, which doesn't affect your attack or defense

And when the process is complete, full health!

Any minor change will do it, so it's usually a good idea to stock up on E.V.O. points before facing a tough challenge.

Play E.V.O. long enough and you'll find this hidden grove of dinosaurs that talk about these weird creatures with the head of a cat and the body of a rabbit.

If you decide to take that fairly obvious clue, you end up with your cat-rabbit thing

From there, choose 'Body' → 'Ramothecus Body' to spend 5000 of your EVO points and become a monkey.

From there, keep going back to 'Body' → 'Evolve Further', and you'll evolve further (duh)

And again

For Human Form!

The human is kind of quick, and has a decent attack with that club. But this is definitely a one-way path. Once you hit this, there's no turning back and no more experimenting with combinations of body parts.

You also might be wondering how the same creature can evolve both into a female mermaid and a male caveman. And to that I'd just like to remind you to repeat to yourself that it's just a game and you should really just relax.

E.V.O. is all about evolving your creature to survive in the different eras of prehistory, and there are a few hidden surprises waiting for you.

For instance. Make it pretty far in to the game and you'll hit the stage Final Ocean

Hop in and you'll be given the ability to swim. But check out the Hands and Feet option in your E.V.O. menu.

Try to evolve and you end up looking like a fish thing.

Go back to Hands and Feet and choose 'Evolve Further' to... evolve further (natch).

And again

And again

Boom! Mermaid!

Why would you want to do this? The mermaid has 100 HP, the strongest bite of any of your creatures so far, and is the fastest swimmer, so there's really no reason to not do it.

Also, once you're finished with this stage, you get your old body back, so enjoy it while you can!