This achievement is horrifically grindy, and probably only takes you about a 1/3 or 1/4 of the way to earning enough XP for Level 50... this achievement took me about 10-12 hours of following the guide below, so be ready for setting your PC aside for maybe up to 40-50 hours if you're going for Level 50 on top of this achievement.
For this achievement I highly recommend download the
AutoHotKey app, as it'll automate this whole process. Credit to user JeroenRos for noting the script, and instructions for how to use it in the Level 50 solution, it's basically the same script, but I added a few lines as I found that the original script wouldn't replay levels correctly.
If you've never used AutoHotKey and are unaware on how to make a script, simply open up a Notepad file, and copy the script i've listed below, then save the file as anything you want to call it, but instead of saving it as a ".txt" file, you'll want to make sure it's saved as a ".ahk" file. Once you've saved and placed it whereever is most convient (for me it was just on my Desktop), just open the file and it'll start running in the background thanks to the AutoHotKey app.
After opening the script, you'll want to start it once you're in a round by pressing both
Left Ctrl + Q, you pause it by pressing
Escape, and to end the script you press both
Left Ctrl + Escape.
Here's the script you'll want to create:
*** Spoiler - click to reveal ***Esc::Reload
^Esc::ExitApp
^q::
Loop
{
SendInput {E down}
Sleep 1000
SendInput {E up}
Sleep 1000
Click 1200, 600
SendInput {E up}
SendInput {E down}
Sleep 1000
SendInput {E down}
Sleep 1000
SendInput {E up}
Sleep 1000
}
What the script does is click the coordinates 1200:600 on your screen, which is where the thumbs up button appears at the end of each round which gives you a 25XP boost for each completed level which only gives you 50XP by itself. You can edit this to work with whatever resolution you've got, but I would recommend just sticking with the games resolution set to about 1920x1080, unless you want to fiddle with the coordinates in the script to fit your given resolution. The game also has to be in focus whenever using the script, so no tabbing out and watching videos.
Once in the games lobby, you'll want to select Community-Made Games from the lobby console, and then search for a map called "
XP Farm" by Mystic Flop. You'll want to queue this map at least 3 times as a precaution. Once done, just start the level and also the script by again press Left Ctrl + Q (unless you've changed the input). Each round takes about 5 seconds until it finishes automatically, then the script thumbs up the map and also prompts the game to replay the round. At the end of each round you'll earn 75XP. Just leave the script running until you get to Level 25, or Level 50 if you're in it for the long haul.
Another tip I recommend is maybe completing some of the Daily Challenges, they're usually pretty simple and can again be done via Community-Made Games, hell you'll probably get one via the automated script as they're usually something on the lines of "Play x amount of Community-Made Levels" or "Rate x amount of Community-Made Levels". These give you 750XP each, which cuts down the time for this achievement by about 30 games per day if you complete all 3 daily challenges.