wow! i just saw your score on the leaderboards!! that's crazy! you're better than I am haha. and to answer your questions:
1. time is only tracked during rounds.
2. spells appear in the order: plant, fire, rocket, shield - with a 10% chance that you'll be offered an upgrade spell instead.
the spells that have upgrades are lightning and the plant spell. you should do a speed run video!! :)