The optimal strategy seems to be to fly around in a wide circle, letting the vipers commit suicide. You'll never be hit unless a viper spawns on top of you.
Great start -- could use a fair bit of work, mainly:
- It's very easy to get into stalemate situations, particularly with the extra-tough towers near the enemy objective. You've effectively won long before you win (for me, it was almost 50 minutes from when the other side had no chance to when I won).
- Taking out the enemy spawn buildings doesn't seem to prevent the spawns. Is this on purpose?
- Performance improvements would be helpful -- the game runs about 1/4 real-time for me, with 4-5 seconds to a game "second"
- Special ability cooldowns are too slow for the rate of gold gain. I never have to choose what abilities to spend gold on
- I'd divorce the shops from actual buildings; allowing buying everywhere would save a pointless trip to town. Likewise, it'd be helpful to be able to control the spawner buildings from anywhere.
Nice variety of enemy patterns / movement; the pacing is quite nice for the first ~12 levels. Then the difficulty tops out, unfortunately. Two simple suggestions other folks have made would make a big difference: challenges and a level indicator.
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