It seems to only work in DOSBox 0.74.
I like the idea (though the movement felt a bit slow) and having the display be a rough map of what is actually there (it kinda reminds me of Thief's "rough" hand-drawn maps and i guess such an idea could be explored more). I think having a bit of more randomization would help. Are there only two levels? After beating the first level i had the second level repeat, though it looks largely the same as the first minus the cameras (...wouldn't that make more sense as the second level? :-P) and i think some bushes are moved differently but it looks largely the same.
In general i found it a very cool idea, even though i'm not really into stealth games :-).