Azgard Defence (Stress) | Защитники Азгарда (Стресс)

Tower defence, where you have to survive 100 waves of enemies. The only difference between levels is the places where you can build towers and the shape of the road. The towers can be leveled up (increases almost all their stats) or upgraded (completely reworks the tower). Upgrade almost always better than leveling up, and leveling up is always better than building an extra tower.
The towers are:
The archer tower - the worst tower in the game but shoots both flying and land monsters. Every it`s upgrade is unique and useful: the poison tower with delayed damage, the corrosive tower with reverse armor effect and the deadly tower with an instant kill chance.
The gun tower - shoots land monsters with a splash attack. Every it`s upgrade has no unique features except the fire tower, which has the burning effect.
The wind tower - shoots at flying enemies. Can be upgraded into the magic tower, which is incredibly broken against all enemies. It can be upgraded into the doom tower, which shoots only at the land monsters but applies both 50% damage vulnerability and slowness with AoE effect. Not as broken as it sounds. Other upgrades can shoot both flying and land monsters with slowing or stopping effects, but the only monsters that cause so much trouble are immune to their effect
The airship - the only unit which can shoot multiple enemies at once. Can be upgraded to mk 2 and mk 3, which shoot with poison and fire respectively.