First level is kinda badly designed, basically you have to create combination of 2 trees until there are 7 trees.

For other levels it is enough to create a word combination stated at the top only once.

This game changes every 10 seconds.

Controls:

Main

WASD to move,

Left mouse button to shoot,

Right mouse button to pick words. 

M to mute music, N to mute sounds.

Word manipulation

Spacebar to swap non-sign words (empty cells swap too!).

Right click to delete a word.

Word rules:

There are 3 ways to create a statement:

1. Two same symbols: tree, tree => more trees

2. Sign (+, -) and object: minus, ruler => make smaller

3. Sign and two object, one of which is modifier (heart, boot and ruler are modifiers): plus, bullet, heart => bullet will pierce targets

From level3, each 10 seconds target changes, from player to enemy. Non neutral statement will affect current target, (more trees is a neutral statement, but more bullets is not)

Notes: 

1. if you don't get hit, something might happen

2. Movable trees are not a thing :(