Here is a strategy I use for Mote-M and I can get up to really high levels. Sorry if this is hard to understand: I make 2 tracks for the enemies, which both start at the beginning hole. The enemies should only be going on 1 of the paths. Next, I fill the track completely with level 4 black pieces and clog the path at the very end that the enemies aren't going to with a level 4 black piece. When the enemies (which should all be on the first track) have almost gotten to the ending hole, I unplug the second abondoned track by upgrading that piece to a 4 so it deletes quickly then i plug up the first track. Then enemies will switch directions and then when they get to the other side, I can just do the same thing. This way they keep switching back and forth and will (hopefully after a little practice by you) never get into the ending hole. So far using this method i have gotten to level 33 and would have gone farther but i had to go.