[Beorn]

Wow, nice one.

I'm currently doing the gold medals on early levels, testing mixes of towers. So far a 50/50 mix of lasers and guns seems to be best, with maybe 2-3 inferno/temporal combos when/where the map calls for it. It looks as though the heat effect of lasers is better $-wise that standard gun but that since it doesn't stack, you max out and need to get gun. Someone also said something on their forum about laser+temporal to set up heat effects on mass crowds instead of using a "brute aoe" inferno but I'm skeptical about that.

I read concussion is better vs shield mass and that well placed cannons rock maze levels, but I'm not there yet. I also read that missile towers are best massed at lvl 1 rather than upgraded since fliers don't have enough HP to warrant higher damage rockets. Apparently, some of the "green towers only" challenges require you to build/sell towers to change paths, aka "juggle" creeps, in order to pass them.

I don't yet know whether mortar, concussion or inferno is best for dealing with masses in general; I suppose concussion is best when you have a sweet round spot, otherwise mortar because it shoots much longer.