I like this, especially the fact that four players can play at the same time. How do you control 4 players? Mouse/keyboard or gamepads?

Hi Severin, thanks!

Mixed, keyboard and/or gamepads...
Four players are all mapped to keyboard buttons, but the keys can be configured on the keyboard any time in the settings menu:

Actions: up, left, down, right and fire

Player 1: Up, Left, Down, Right and Right Control
Player 2: W, A, S, D and R
Player 3: I, J, K, L and P
Player 4: Numpad8, Numpad4, Numpad5, Numpad6 and Numpad0

Also, any player can change to a gamepad, since four gamepads are supported by the game. Both keyboard and gamepad control works for a given player at the same time.
On gamepads DPads and ThumbSticks control the player movement and any other button can be used for firing.

Br.

Cool. I did not checked all your posts but could you please explain what mutators do.

This constantly growing kreep slime in a multiplayer shooter game is really a good I idea I would gladly work on a similar game too :)

Yep, mutators are sort of like "game modes" but they are not exclusive, so they can be combined.
They "mutate" the base rule set for achieving a different experience, be it harder, more strategic, more hectic, or simply funny :)!

Some examples from KREEP:

KREEP eats people! -> The KREEP has a higher chance to eat nearby players (sort of like really hard mode :D).
Rocket launchers -> Instead of laser rifles the players have rocket launchers equipped which fire slow moving explosive projectiles.
Energy shield -> Players spawn with a personal energy shield, which saves from one hit.
Last man standing -> No infinite spawning, each player has four lives and it is over.
...

So these can be set for any game you play, so you could play a "Last man standing" match with "Energy shield" active too etc...

The 1.1 version of the game adds 3 new unique mutators. The trailer presents 2 from the new ones, one for turning props into explosives and one where the KREEP not only grows, but jumps around from tile to tile, making it's movement/growth even more unpredictable.