Changed the save system for better performance and later updates. Old save file will not work anymore but new one should be compatible with newer versions of the game.
Increased the difficulty.
Added a retirement system and a shop in the main menu. Players can now retire with their current class / main char to get credits based on their performance. Credits can be spend to buy perma upgrades (currently just 3, more will be added later).
Added a short tutorial which explains the basics.
Reworked the UI a bit, now you can close windows by pressing the right mouse button instead of X.