ive played the demo.
theres a machine gun there (see pic).
now ive bought the full game.
but i dont see it anywhere in the full one.
do i maybe have to complete more missions??

(im in chapter/level 21)

The 'sentry gun' is only on certain pre-made schemes, such as Pro and Darkside. If you create a scheme based on one of those, you'll get the sentry gun in that scheme.
It can't be unlocked normally.

i guess you have to buy it in the shop first don't you?

Nope, no shop. Only in thise schemes, or pray you get it from a weapon crate. :P

really? you can't put the sentry gun in a selfmade sheme?:(
that sucks...
i've never tried it yet but i was looking forward to do it

really? you can't put the sentry gun in a selfmade sheme?:(

You can, if you make the scheme by editing one of the ones that already has it in. It's not ideal, but it works (unless Plasma is lying).

The other way is to edit one of those files in the 'tweak' folder, so that one of the premade schemes has changed, then base it off that and change the origional scheme back. I can't remember which file though.

If your, like, DESPRATE to use it, then play the tutorial. you'll find it on the robot level. hope it helps