What i forgot now that im thinking about it: Rocket Towers should be the best towers you have in the game. Make the rockets retargeting and also increase their fire rate with upgrades.
It is great to have upgrades for the towers but you should make a cap. ATM all it needs are 2 machine gun towers and upgrade them all the time to win this game. Just make it only possible to upgrade up to 5 times and also tweak the machine gun tower so that fire rate does not increase with the upgrade.
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