This is for the current Steam version (1.2.20333).
I managed to enable Debug Tools for the game but so far, I haven't found a whole lot to do. Was hoping for a character editor or console window but no dice. Press U once or twice to make button appear in upper right corner.
Spawn Patients - You can choose their illness from a scroll window then click somewhere ingame and one will spawn in at map edge.
Delete Characters - Removes all NPCs from hospital. Will have to rehire new employees if used. Seems to stop future patients from arriving though. Will have to use events to get patients.
Delete Patients - Removes all current patients in hospital with a successful cure result. Seems to stop future patients from arriving though. Will have to use events to get patients.
Clean Tiles - Can make tiles clean or dirty by clicking this.
Add Floor - Does what it says. Adds a new floor with the same walls and tiles as the current top-most floor.
Reset Time - Sets time to Day 1 at 08:00.
Reset Money - Sets money to the default amount you start with.
Test Event - Starts a random event.
Collapse Low/Medium/High - Selected patient will collapse with a symptom. Low is exhaustion, Medium is Hypovolemic Shock and High is Heart Failure.
Unlock All - Unlocks all departments from the start.
Reset Unlocks - Locks all departments.
Non-Functioning (?) and external buttons:
Add Test Char - Doesn't seem to do anything.
Reload Textures - I assume it does what it says but I am put in a permanent load screen.
Memory Stats and Memory Dump - I assume dumps this to a txt file somewhere.
Reset all patients and staff - Doesn't seem to do anything though the game freezes momentarily as if it is.
Edit: There are also some Debug toggles below those buttons. They have varying uses but and example is the Debug_Inspector which will show you detailed information for any character you select. Non-editable though.
Edit 2: Apparently, someone had found this a couple months ago, reading back through some posts. Oh well. I'll leave this here.
Download the .zip from here. Password is Fearless. Extract .zip
Go to your game directory. Mine is: D:\Program Files (x86)\Steam\steamapps\common\Project Hospital
Navigate to ProjectHospital_Data > Managed and rename Assembly-CSharp.dll to Assembly-CSharp.dll.bak to make a backup and move the extracted one to that folder. Launch the game and go into a map. Press U a couple of times to make the Debug icon appear.