I, too, cannot launch it via the main menu entry in my KDE desktop any more. I can only start it from within CKAN. When I run the start script manually, I get:
/mnt/data/games/ksp ./start.sh
Running Kerbal Space Program
support/gog_com.shlib: Zeile 105: cd: /mnt/data/games/ksp/game/64: No such file or directory
support/gog_com.shlib: Zeile 106: ./ShovelKnight: No such file or directory

It seems as if the start script belongs to Shovel Knight, another game on GOG.

Can you try to reproduce?: Open a terminal in the directory where you installed ksp and enter ./start.sh
What output are you getting?

Thanks felf
I can confirm your findings

had a look at start.sh

will try to edit it and see if it will launch

run_game() {
echo "Running ${GAME_NAME}"
local bin32_name="ShovelKnight"
local bin64_name="ShovelKnight"
local bin_path32="$CURRENT_DIR/game/32"
local bin_path64="$CURRENT_DIR/game/64"
local lib_path32="$CURRENT_DIR/game/32/lib"
local lib_path64="$CURRENT_DIR/game/64/lib"
execute_game "${bin32_name}" "${bin64_name}" "${bin_path32}" "${bin_path64}" "${lib_path32}" "${lib_path64}"
}

The start.sh is messed up use the one for 1.11 it works fine will try to attach it for anyone who needs it until GOG updates the install

Sorry its a jpg small amount of typing required can`t post sh file here


Just clicked that I could copy paste the txt

overwrite the contents of your start.sh with the following code
it worked for me including both DLC`s

Best of Luck and have fun

#!/bin/bash
# GOG.com (www.gog.com)
# Game

# Initialization
CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
cd "${CURRENT_DIR}"
source support/gog_com.shlib

# Game info
GAME_NAME="$(get_gameinfo 1)"
VERSION="$(get_gameinfo 2)"
VERSION_DEV="$(get_gameinfo 3)"

# Actions
run_game() {
echo "Running ${GAME_NAME}"
cd "${CURRENT_DIR}/game"
chmod +x *
./"KSP.x86_64"

}
default() {
run_game
}

# Options
define_option "-s" "--start" "start ${GAME_NAME}" "run_game" "$@"

# Defaults
#standard_options "$@"