diff --git a/README.md b/README.md
index ed42efc..810380b 100644
--- a/README.md
+++ b/README.md
@@ -1,64 +1,138 @@
-## Godot regression test project
-This repository contains Godot project which is tested in offical Godot repository(3.2 branch)
+# Godot regression test project
+This repository contains project which is used to find regressions in Godot.
 
-It aims to be complex project, which will allow to find crashes, leaks and invalid memory writes before PR is merged.
+It aims to check as much as possible functions and states, be easy in maintain and provide reproducible results.
 
-Sadly it can't find automatically any logic errors.
+## Basic Informations
+This project contains a few different scenes and `Start.tscn`(default one) which opens every other scene. 
 
-## Reproduce bugs
-If CI find bug, you can easily without much effort check which scene cause problems(stacktrace, address or leak sanitizer log will be available).
+List of this scenes are available in `Autoload.gd` file.
 
-All main scenes are independent of each other(only `Autoload.gd` is required), so it is easy to disable some for testing.
+![B](https://user-images.githubusercontent.com/41945903/104442905-060e7c00-5596-11eb-9000-f9bb338ece79.png)
 
-To create minimal test scene:
-- Look at the console output - there is printed info about current used scene
-- If you run `Start.tscn` scene(which run other scenes in queue) then you can modify list of scenes which needs to be run in `Autoload.gd` by commenting records in `alone_steps` or `all_in_one` array(just like in picture)
-![Zrzut ekranu z 2021-01-13 11-52-41](https://user-images.githubusercontent.com/41945903/104442905-060e7c00-5596-11eb-9000-f9bb338ece79.png)
+It is possible manually set how long project need to be executed from command line, just by adding at the end number of seconds - `godot 40`.
 
-## How it works?
+At first `all_in_one` scenes opens, execute `_ready` function and exit. 
+
+The available time(default 25s) is divided equally between each scene in `alone_steps`.
+
+Then, one by one, each scene is created and after a certain amount of time it is deleted and another scene from the `alone_steps` takes its place.
+
+This project is running in CI with a version of Godot compiled with Address and Undefined sanitizers(`scons use_asan=yes use_ubsan=yes`) so without these options it won't always be possible to detect the bug or get so detailed backtrace.
+
+## Searching for a malfunctioning scene
+### Logs
+When searching through the logs for the error you may come across something like this
+```
+Changed scene to res://Rendering/Lights2D/Lights2D.tscn
+Test is running now 35 seconds
+Test is running now 40 seconds
+Changed scene to res://Rendering/Lights3D/Lights3D.tscn
+##### CRASH #####
+Godot crashed with signal ...
+```
+This log indicates 2 potentially broken scenes
+- `Lights3D.tscn` - crash occured because scene started work
+- `Lights2D.tscn` - crash occured because scene was removed
 ### Autoload
-There is only one scene which is loaded when project starts - "Autoload.gd".
-It handle exiting project after selected number of seconds
+You can freely comment out selected lines in `alone_steps` or `all_in_one` to choose which scenes will run `Start.tscn`.  
+You can also use `time_to_show` variable to set time how long the project will run.  
 
-When opening any scene, automatically time to exit is set.
+![Autoloads](https://user-images.githubusercontent.com/41945903/115044743-16582f00-9ed6-11eb-889f-4f07ad6c7d13.png)
 
-If running projet with e.g. this parameters
+### File System
+The last way is to manually run each scene from the file system to find the one malfunctioning.
+
+![File](https://user-images.githubusercontent.com/41945903/115044733-13f5d500-9ed6-11eb-9364-43a1a142a6f1.png)
+
+## "Safe" fuzzer
+A scene that will probably give people a hard time quite often is `FunctionExecutor.tscn`.  
+This is a fuzzer, but with removed ability to use random argument values (the arguments are identical every time it is run).  
+When the engine crashes, in logs usually will be something like this:
 ```
-godot 20 
+#################### SkeletonModification2DPhysicalBones ####################
+SkeletonModification2DPhysicalBones.set_physical_bone_node
+Parameters [100, ]
+ERROR: Joint index out of range!
+   at: set_physical_bone_node (scene/resources/skeleton_modification_2d_physicalbones.cpp:259)
+SkeletonModification2DPhysicalBones.get_physical_bone_node
+Parameters [100]
+ERROR: Joint index out of range!
+   at: get_physical_bone_node (scene/resources/skeleton_modification_2d_physicalbones.cpp:265)
+SkeletonModification2DPhysicalBones.fetch_physical_bones
+Parameters []
+scene/resources/skeleton_modification_2d_physicalbones.cpp:186:2: runtime error: member access within null pointer of type 'struct SkeletonModificationStack2D'
+handle_crash: Program crashed with signal 11
+Dumping the backtrace. Please include this when reporting the bug on godotengine/godot/issues
+[1] bin/godot.linuxbsd.tools.64s() [0x1e697d8] (/home/runner/work/godot/godot/platform/linuxbsd/crash_handler_linuxbsd.cpp:54)
+[2] /lib/x86_64-linux-gnu/libc.so.6(+0x46210) [0x7fd1ca5b0210] (??:0)
 ```
-Then time is set to 20 seconds so it means that if scenes is 10 (EACH in `alone_steps` array + one for ALL scenes in `all_in_one` array), then each scene will be show for 2 seconds
-
-### Checking All scenes at once
-There are two scenes which opens all scenes:
-- All.tscn - opens all scenes at once
-- Start.tscn - opens each scene one by one
-
-### "Safe" Fuzzer
-Available inside `AutomaticBugs` directory, check all methods with specific arguments in allowed classes.  
-During calculations, to output should be written informations about current classes and executed functions with arguments e.g.
+There are some interesting things to discuss here.  
+This line shows what class we are testing now
 ```
-############### CLASS ############### - PopupMenu
-add_icon_radio_check_shortcut
-Parameters [[InputEventMouseMotion:12379], [SoftBody:12380], -109, True]
+#################### SkeletonModification2DPhysicalBones ####################
+```
+which method
+```
+SkeletonModification2DPhysicalBones.set_physical_bone_node
+```
+and which parameters (here are two arguments - `100`,  \` \`(empty string))
+```
+Parameters [100, ]
+```
+To make testing easier, each object is created from scratch and by looking at the class definition in Godot - `set_physical_bone_node(int, String)` we can create an expression that is executed on this line:
+```
+SkeletonModification2DPhysicalBones.new().set_physical_bone_node(100,"")
+```
+Then you can see errors caused by invalid arguments, which you can ignore if they don't cause other crashes/leaks etc.
+```
+ERROR: Joint index out of range!
+   at: get_physical_bone_node (scene/resources/skeleton_modification_2d_physicalbones.cpp:265)
+```
+At the end we can see Godot's crash log with additional information that tried to use null pointer incorrectly:
+```
+scene/resources/skeleton_modification_2d_physicalbones.cpp:186:2: runtime error: member access within null pointer of type 'struct SkeletonModificationStack2D'
+handle_crash: Program crashed with signal 11
+Dumping the backtrace. Please include this when reporting the bug on godotengine/godot/issues
+[1] bin/godot.linuxbsd.tools.64s() [0x1e697d8] (/home/runner/work/godot/godot/platform/linuxbsd/crash_handler_linuxbsd.cpp:54)
+[2] /lib/x86_64-linux-gnu/libc.so.6(+0x46210) [0x7fd1ca5b0210] (??:0)
+```
+we can assume that this is caused by calling the function immediately before the crash:
+```
+SkeletonModification2DPhysicalBones.fetch_physical_bones
+Parameters []
+```
+We can test this by running a function in Godot that looks like this(just add `.new()` after class name and fill function arguments from `Parameters`):
+```
+SkeletonModification2DPhysicalBones.new().fetch_physical_bones()
 ```
-This fuzzer should in most situations be safe to use, because always use same set of arguments in functions, and objects are cleared before executing next function.  
 
-This tool is developed in external repository - https://github.com/qarmin/Qarminer.
+## Nodes
+Scene simply adds and removes at once all available nodes.   
+It is used to catch early very obvious and easy to reproduce bugs.
 
-### AIO
-This are scenes which only opens once, because there is no need to open it more times - used to check loading of specific types of nodes or executing its `_ready` functions.
+## ReparentingDeleting
+This is more advanced variation of Nodes scene.  
+In random order adds, remove and move in scene tree nodes. It may not sound spectacular, but it sometimes allows you to find bugs that are hard to detect.
 
-### MainScenes
-Collections of all nodes, which are after some time simply removed and added to scene.
+## Others
+Scenes like `Physics2D.tscn` or `Lights3D.tscn` are normal scenes with specific types of nodes. They are only used to manually check visual differences between different Godot versions.
 
-### ReparentingDeleting
-This scene randomly reparent, add or delete nodes inside it, to check correctness this operations.
+![Physics](https://user-images.githubusercontent.com/41945903/115050994-9da8a100-9edc-11eb-99f6-9375ef917be1.png)
 
-### Other Scenes
-Each other scenes checks specific types of nodes like lights, rendering, physics, text.
+## TODO
+- Add physics test - currently blocked by several crashes - https://github.com/godotengine/godot/issues/47440
+
+## 4.0 version limitations
+ReparentingDeleting is in 4.0 only Reparenting - bug https://github.com/godotengine/godot/issues/45471  
+Some scenes available in 3.x branch, but due freezes and long loading times are disabled.
 
 ## Epilepsy Warning
 Due using by project a lot of functions from each type of Node, screen may flicker, images and objects may change randomly color and size which may lead some users to health problems.
 
 ## Problems with project
+The project should not cause too many problems in CI when adding and removing features in Godot, since it don't uses too much functions but for example removing a base type e.g. `TYPE_INT` or changes in GDScript(e.g. changing `instance` to `instantiate`) can mess it up.
+
 If you have problem with this project e.g. in CI, just ping me -> @qarmin <- and after that I will try help to fix issues which you have with it or add exception to project.
+
+