The game requires a considerabile ammount of grinding to take every single Achievement but luckily, because of the intrinsic semplicity of game-play, there could be ways to actually perform this task while away from keyboard.

Let's be transparent: the game is quite repetitive in single-player and most of people are unable to play with friends so much, at least not this game, to visit 5000 rooms.
Taking the last achievement requires a considerable grinding effort, but luckily the game-play has a notable intrinsic semplicity; even a bot could try to play this game and possibly win some match.
If you are not able to program, just like myself, it could seem hard to create an automation able to restart the match after both winning or losing and actually play the game in an acceptable manner.
But experimentation, as explained in the next sections, proves that also the game has natural dynamics to help you in this task, and this solution is therefore achievable.

As totally incompetent in programming tasks I have decided to follow a step by step video from Youtube:


It was posted 3 years ago as I am writing this in March 2024, so the files to install now have been updated and have different names currently. I haven't been able to find the "community version" of Pycharm, but the 30-days free version works just fine.

After succeding in creating the basic automation as shown in the video, the author explains (minute 1:15) that you have to insert the inputs that the program is going to use; I have written, and you can freely copy-paste:

while True:
PressKey(17)
time.sleep(2)
ReleaseKey(17)
PressKey(18)
time.sleep(.1)
ReleaseKey(18)

The automation will be able to just walk forward and open the doors when it finds them, but it is acceptable.
To make it work you have to:

• Open the game normally
  
• Reduce it to a window (so that while in the menu or in the lobby you are able to move your cursor out of it)
  
• Open your Pycharm automation
  
• Press the Play Icon on the top of the "Run/Debug Configuration" window (in which you have written or copy pasted the entire program if you did everything correctly)
  
• Come back in your game and start a match

You will notice that the character will immediately start to walk straight forward and open the doors when it finds them. You can, anyway, move your cursor to change its direction to make it walk directly to the doors.

When the match finishes, because the character has just both died or won, the game will count in reverse from 20 to 0 and a new match will start, so you don't have to worry about make it replay the game, it is already able to do so.
Anyway your character may change its direction during the game because of the obstacles it finds in its way. I found that the fastest way to start back a game when it happens is to play in non-stop mode with the least time (20 seconds) permitted in a singular room so that if it stucks in a corner it will just die and start a new match soon. I used to put the biggest map possible (13 x 13) to minimize the chances of facing a closed door.

So usually I started a new game with this method, make the character walk in the most straight direction possible facing a door and then put the screen in sleep mode to make it play the game while away from keyboard.

This method is not very fast, but it works.
I started following this method with about 4 scarce hours of play, about 500 rooms visited and almost 200 traps found, and ended up taking the infamous God Explorer achievement at 127 hours of play so it took me 123 hours.
In other terms I used to make it run during the night, except from two occasions when it continued uninterruptedly from 22 to 18 of the next day, and it took about 9 or 10 days.

There could be ways to make the character move faster like changing the code to make it press L-Shift permanently, but I haven't succeded in doing so, I wish good luck to everybody interested in trying this way.
Another thing that can be tried is experimenting a little more with the inputs written. I am referring in particular to the walk time.sleep of 2 seconds I decided to use. Maybe lowering it could be a way to make your character open doors faster, but I haven't tried it.
Thank you for the attention.