I'm having a hard time getting functional walking...? I turned up the speed a lot, but it never seemed to improve.
Reset the game. Don't change the Speed. Turn off Terrain. Click "New Lifeform", until you get something promising. Add a few bumps on the track, as in the Gifs. Let the game run by itself for a while. Sometimes, it can take up to 10,000 rounds before you see progress. That is how evolution is. Don't increase the speed to wait less, it doesn't work that way. It is an experimental setting and will most likely not give you what you want. I've had success leaving the game running all night. This is why it Auto-saves, because you need to keep working on a lifeform for a long time.
Hope this helps!