The message Azou got is obviously Windows, I can tell...
The problem can either be because Windows kills the proccess bacause of CPU usage
tekdino wrote:when in GE press ctrl+alt+del and you will get the task manager. Now choose the 3rd tab (in english something like capasity or CPU usage) There you will see a green line showing how many % of your maximun processor capacity is used. The task manager will normally stay in the top as default. Now start the game mode and see how the green line affects. Then when you close game mode look again at the green line. Does it jump to 100% the same time GE autocloses?
If not, we'll propably need help of Makslane with this problem.
Nothing better I can say than that, but there might be another problem, which is with GE itself, which might mean you need to reinstall it
Anyway, In Squareland Wars I've got like 500 actors or more, and GE works fine.
OK, it slows down a bit, I have to admit, but nothing goes wrong!