I think a speed button would help.
As for a tip on Bowl. Forget the "drone" power, build two lines of collectors up to the left and right side of the trench and put a blaster on each. Keep your starvation low so it moves faster. Once you have that build up a line of collectors to the "drone" power. Put a blaster or two there. Put three 'sams's to protect the three choke points. Now build up the bowl to your liking.
Just because there is no hard evidence to prove they did... Most people still associate horned helmets with vikings.
And i swear i have played this before...
Loved it....
A note: if you only miss the height by a foot or two, try to bomb again and see if they fall in a different way. This works for me on most of the levels.
I say the quickest and most easy route would be start with the most modern and work you way back in time, then move forward in time.
And on the plant... let time pass before you try to dig it up.
Also, i only found 8 critters!