Hi Sung, thanks for the reply. Only 3 weeks is impressive, though I see from the indie subsim forum that you have quite some experience with game making already.
Someday I'd like to start this kind of project, probably a loose remake of an old DOS game. It's a logical step I think after modding, lots more to learn and more liberty
Good luck with the rest of the work, it looks nice so far, love the graphic style.