Changelog:

• 4 new enemies with various abilities
• 2 new multi-block turrets
• New resource: uranium. Used as ammo for the new turrets, and as a source of power
• New power system: generate and transmit power using lasers. Take the new tutorial to learn how to use it.
• New power generators that use uranium, coal, lava or oil to generate power
• 11 new maps, with 2 new liquids and many new block types. Every old map except maze has been removed.
• Completely new wave patterns, with enemies of specific types at specific waves instead of a mix of all enemies every wave.
• New 2x2 defense blocks for steel, titanium and dirium
• New crafting blocks for producing coal and steel
• New transportation blocks: teleporters, sorters, tunnels, liquid junctions, upgraded conveyors
• New defense blocks: shields and shielded walls, both of which use power
• New upgraded pump
• Door blocks, in 1x1 and 2x2 variants
• Repair turrets now use power, as they were too easy to spam before
• New extended description and stats menu for all blocks
• More save slots
• Control change: ctrl-scrollwheel to zoom, scrollwheel to rotate blocks (R and E can still be used to rotate too)
• New UI for many things
• New SFX
• New visual effects for turrets, such as railguns
• Noticeable performance improvements for large bases, especially on mobile (and most likely, HTML5)
• New smarter AI that may avoid small passages and will get stuck on blocks less often
• New enemy flocking behavior
• Many, many other fixes and additions

Next updates will focus on usability and the possibility of multiplayer, instead of content. I'll probably be taking a small break from development now.