There is actually an assist system, from tanki online wiki: when an enemy tank is destroyed by several allies then all of them receive 15 XP in total. Each of these kills also gives 50% more crystals to the battle fund. It doesn't matter who finished the enemy as the score is divided between allies according to how much damage each of them dealt.
This game doesn't need mouse aiming, it adds unique challenge, and it's all about fighting with what you have instead MOAR weapons more upgrades and crystals so that we would max all till the end after few mins and nuke them all without any effort.. shut up kids.
Why does everybody gives this chapter one star rating? Just because of fog puzzle? If you are dumb, and can't solve it, it's your own problem. I really enjoyed this chapter, the atmosphere of these dull, haunting streets is amazing! Not to mention interesting characters, and unpredictable ending, which only makes you to think what will happen next? It's like a mini interactive movie.
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 "The Last Door - Chapter 3: The Four Witnesses"){kind=icon}