physics, swords, guns, explosives,and even elements, and a few freaky ones. Also you guys should add Armour to put on the character and a whole lot more helmets. But please please please for god's sake, add slow-mo just by the click of a button.
I like all the futuristic aliens, but there should of been more species or tougher opponents since I have seen people be more attracted to them, like the dragon , magic, sorcery , upgrades. Also it would be sweet if in the next kingdom rush if you're making one, you should be able to choose different abilities in a slot for even the lowest rank of barracks to the highest rank of the explosive dwarf machine things.
You guys should fix the joining game problem and make the permission buttin something easy like (SHIFT+Y) for yes and (SHIFT+N) for no or just pop up a screen to say yes or no
Slow-motion can be keymapped. It should be [G] by default.