I really dont like how it starts each of the later levels with various units. Free guys are nice, but it kinda messes with my strategy. (i like to go tons of 1 or 2 unit). Some of my favorite combos are: archer/spearton, tons of ninjas, or giant/cleric.
The freeze debuff is painfully inconsistent. sometimes it will prevent me from moving. sometimes it won't let me attack. on occasion, both will happen at once. This debuff is so terrible, it made me want to stop playing all on its own.
I started to boost while holding down the gas (I use WASD). Next thing I knew, chrome disappeared. I was so confused until I realized CTRL+W is the hotkey to close a window.