Anyone with over 100 words per minute must be cheating. I was typing "poi" a million times with only my right hand (pinky on enter, crazy fast rocking motion) I only managed about 90 wpm before my hand spazzed out.
I love the physics of the boiler. I can just knock letters around and watch those little bubbles for a half an hour at a time. Maybe the game's brain-numbing effect has made me more easily entertained.
I don't think you should be able to reassign points. At least not mid-game. It allows for too much corner-cutting. If you get about 40 points, you can maximize mana pool and start with two fully upgraded towers. Then you can switch and put in knights. Then you can remove those points so archers can't spawn anymore. After that, upgrade attack and defense and let the game beat 30 waves for you.