To resize the window please do the following:
1. Close the Game
2. Open the \bin folder in your Dekaron installation folder.
3. Open the 'option.txt' file (with Notepad or another text editor).
4. Search for 'display'. Change the first number for 'width', second for 'height', and third for 'Color Bit Depth' (usually '16' or '24' or '32').