Pining for something like the early stages of aspire, I downloaded this. It is very like the first stage, without the ability to freely design your creature. This has fairly linear progression, but is still a decent “quick fix.” It is over quickly, since there is nothing to do after completing all the evolutionary trees, which can be done in a couple hours.
The issue comes from the ridiculous ads. Seriously, ads start playing randomly and can come so often that not even a minute has passed. This is bad when you are trying to flee from a predator or are low on health. It nearly made the game unplayable before I put my phone in airplane mode. Doing that will have one ad play and then make the game ad free until you turn off airplane mode.
All in all, not a terrible time killer. Actually pretty decent if you have a method to reduce or circumvent the inconvenient ads.