Okay, an update before I stop for today.  You can now scan the fungi (and win the game if you scan all the fungus types), and toadstools attached to your ship fire bullets and destroy fungi:

Things to do tomorrow:

• Music.
• SFX.
• Falling boulders.
• Shooter fungus?
• More fungi.
• Foreground drop shadows.
• Scanning progress bar.
• New ship.
• Title screen.