The game is great, but sadly, it suffers from the same problem old games often suffer: horrendous stability. It's one of those games which never worked properly for me. I've played it throughout the years on multiple systems, since the first week it was released. The GOG version, sadly, doesn't make any difference. Saving is no fix. The save system during missions is useless. You can "save", but it doesn't do anything. It doesn't record your progress, it literally has no use. This is infuriating, since missions can often be very long. When taking things slow on a longer stage, a mission can very easily last 1 hour. If you buy this game, at least play it ASAP, so you can get a refund if it doesn't work. It's a shame, because it's a good game, but the stability is a crapshoot.