How to record your gameplay in video games?

Press F1 and type in "record name".
Replace "name" with the name you want the demo to have.
When you're finished, press F1 again and type "stoprecord".

ESC: SETTINGS: CONTROLS: change console key to anything.

if you're in the server browser, click "settings" in top right...

if you're in a game, click esc and settings.

in user/appdata/roaming/teeworlds/demos

Ok thanks, how do you take them out and make montages out of them?
do you go in the data and its somewhere in there?

Use xinit to start another xserver on display :2 with only teeworlds as client. Set a low game resolution. Use ffmpeg to grab the display:
ffmpeg -f x11grab -s cif -r 25 -i :2 ~/movie.avi
... or something like that.

After testing, you could just put that stuff into two scripts (one to start xinit + ffmpeg, one to be the xinit main process that starts teeworlds, sets config file / screen resolution etc) if you're planning to do it often and use $1 and $2 for demo name + output filename. I'm not sure, if ffmpeg's x11grab does work with a dummy display, too, but just try: that would make it even more comfortable to just "convert" demos to videos right from within your main session / favourite file managers right click menu or whatever you use.

wat program u use to record?

Taksi, free reorder, i cant pay for one

I suggest Fraps

Edit: Ok free program,whatever -_-

Fraps - the good and free program, a lot of movemakers use it.

WrX is a pirate