what are these combos you speak of?
idk I never figured out how to use it.
place a combonly somewhere, and then very close to it make sure you have 2 blue turrets and 1 red turret with maxed out damage (u only have to have damage maxed out) 2 blues and 1 red either gives u nukes or upgraded mines
make sure no other units are really close, they can be kinda close but it sometimes doesnt work for me if the other ones are too close,, make sure ur three turrets are touching or almost though
and then when you have all 3 turrets damage maxed out, it will start to change colors, from blue to red and back and forth if u did what i said correctly
then you just clik it when its red to get nukes, blue gives u a turret that shoots big *** mines onto the track, if its too laggy cuz ur really far in it will be really hard to pick the right color, pause the game when it starts to change colors and u can pick the color u want lag free
you can do a bunch of different combinations but nukes work the best for getting past wave 600, my pic shows u kinda the jist of it
if u wanna try other combos, **** around with the 4 types of turrets, just make sure u max out their damage or it wont work
also, the combo turrets cant be rate-modded, but can be damage-modded and range-modded so you can stack a bunch of 100% damage on the nukes and be happy til at least wave 550
edit: to show u what i mean, here the pic again, the nukes are all along the left with the damage mods
