Here's solution:

Put in your Internet browser this steam://nav/console and press Enter.
You open console at Steam.

Now at Steam Console copy this:
download_depot 1287150 1287152 4663958736027817820 and press Enter.

After Steam download depot, go and copy all you find here:
C:\Program Files (x86)\Steam\steamapps\content\app_1287150\depot_1287152

Now go where your original game is installed and deleted all there and put all what you copy at Steam depot.

That's it :) Go launch the game like you originally launched and choose Multiplayer, than Host Game.
In Select Map option choose - 1v1_Volleyball
In Gun Power option choose - 9000

Now push Host Game, than big button START and shoot one time at the ball behind you.

You did it :) You get 2 broken achievements:

Play Volleyball
.


Over 9000 Power Level
It's over 9000!

As the developer wrote in this post: https://psteamcommunity.yuanyoumao.com/app/1287150/eventcomments/2997674644684454057/


The tournament will be played on a separate build of Pulseball which you can access via these instructions:

1. Go to your steam library, locate pulseball
2. Right click it and select "properties"
3. Go to "betas" and put in the code "extremespots" (no quotes)
4. Download the update and play


Go launch the game like you originally launched and...
At the Main Menu choose Play, than Multiplayer Host Game, than Play.
At the match shoot one time at the ball.

You get achievement:

Competitor
Take part in the annual end of the year pulseball tournament