The game is so slow it's unplayable. I've tried it as is, horribly slow. I've switched to 3dfx mode, it's even slower. I've tried to manually configure stuff in DosBox (isn't the whole point of buying a GOG realease to not having to do this?), slightly better but still unplayable. I even installed nlgide and followed jaybirdwarrior's description, the game was uglier than ever and still very slow. Much-much slower than on my good old AMD K5PR100 and 32 MB RAM, which wasn't even a good configuration even 25 years ago :D I wish I could ask for a refund, but I'm out of the 30 days limit.
