To be honest, I like the idea and the approach. However, I'm not running that old of an machine and am getting incredible lag. After all, if it's designed like an old DOS game then shouldn't it also have the same demands in terms of processing power? Something to do with your level design I think...maybe it is all loaded at once instead of in sectors? Dunno.
I think the first update you make SHOULD be the dynamite! and either adjust framerate (which seems to waver), or optimize the way levels load or something.
out of 10...
gfx - 9
sfx - 8.5
design - 7.5
gameplay - 8
overall, I love the idea and it is a charming game hindered only by slight lag at times.
out of 10...