DOS Games made for DOS require an emulator to run on Windows. Use DOSBox or a frontend like D-Fend Reloaded and read this guide to play DOS games on your Windows PC.
The game was re-released by Sierra On-Line for Windows in 1995 under the title Command:Aces of the deep. It updated the graphics to a higher resolution.
There is also an in-game manual that covers the development of the U-Boat, time-line based maps that show kill-to-lose ratios, and, on the CD-Rom version, video interviews with former German U-Boat captains.
The above text is licensed under the GNU Free Documentation License. This text is based on this Wikipedia article.
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