Leaks. You use waits, which leak.
Your special effects happen ten times a second, which will most likely cause lag.
Also, in the loop2 trigger that moves the axes, its set on every .02 seconds. Thats 50 times a second, which will also cause lag.
And the axes repeatedly cause damage, which is probably intended, but will do major damage for lowest levels.
50 times a second times the damage is done.
In other words, 50 times, at level three, will do 75 damage.
If I'm not a bit rusty in math, 50 x 75 is 3750. 3750 from a spell that probably is only meant to do 300 or so. Ouch.
To fix this, add the unit it hits to a unitgroup. When it damages, give the unit spell immunity for .50 seconds or even add the unit to a unitgroup. When it damages, Pick all units matching condition "Not in the unit-group" or something like that.
Edit:
So my rating,
Eye Candy(Appeal) : 5/5
Efficiency : 1/5
MUI : 5/5
So in other words:
5 + 1 + 5 = 11
5 + 5 + 5 = 15
11/15 / 3 = 3/5
~DooM