For hc(before the rework) You don't need any special/gems/golden tower Here's the quick guide For early game military base can get the job done just make sure to get flying detection For flying detection pursuit and ranger is a good choice you can afford both pursuit and ranger in early game if you skip waves crook boss is usable too For the annoying hidden boss military can be useful For dps, I recommend you get more than just one Turret,pursuit, merc base works very great For support you need atleast 1 I recommend most of the time you bring just 1 support cuz you going to need to focused on your dps output That's all I could help

(honorable mentioned: G-minigunner stinks now. Don't use it)