
I fixed up thermo's method and now it's only 1 trigger, so its just as easy to use as the "set to 0 kill score" method.
By some method I mean I've seen these:
Conditional of there being no computer units left:
a) Order 1 unit at a location to move to another location, whatever unit arrives at that location is the next level, then remove that unit in prep for the next level.
b) death scores
c) switches
d) A location containing all the levels' units, left to right. For level 1 to start there has to be the level 1 unit (which is then removed). For level 2 to start there has to be the level 2 unit, but no level 1. For 3, there is a 3 but no 2. Etc.