There was some problems and i already got quite a lot of feedback about things that need to be changed, so i decided to fix it as soon as i could. So here's the changelog:

• increased maximum hp from 150 to 300.
• changed hud a bit.
• fixed the bug with completed tutorial.
• you can now go to a level with a single click instead of a double click.
• increased the time between waves from 1 second to 2 seconds.
• decreased amount of waves on different levels.
• increased the size of some levels.
• enemy spawners now flash white before spawning enemies.
• better saving.
• hp now decreases a bit more slowly.
• better windom scalling.
• new visual effects.

I hope the game is more playable and enjoyable now.