Hey there! Glad you like the game ^^
I actually didn't code the game in a traditional way. I used a program called 'Multimedia Fusion 2', which operates with some sort of script language similar to those used in a lof of RTS map editors (WarCraft III to be specific). Since I'm familiar with those, I got into MMF2 quite fast and started out making some very basic games (GunDude, GunGirl 1). While making those games, I collected a lot of intersting ideas to make a
real game with better and more interesting gameplay and I started with GG2. At first, I just made an exact copy of GunGirl 1 with all features and then I improved on it. GunGirl 1 had problems handeling a lot of enemies at the same time - but with GunGirl 2 I made an example map with over 600 zombies running around and the engine still ran at full FPS.
I started adding more and more features to GG2 and so it became what it is right now.
The most time consuming element was the graphic. It took a lot of time drawing all the animations and enemies, weapons, reload animations, backgrounds, tilesets etc. Some people say the graphics in the game are too childish, but that was my point. I wanted a cartoonish game, because I like bright colorful cartoon styles, but I added lots of violence to make clear that this is still a game for adults. Of course I had to draw a line at some point, because it's impossible to create the 'perfect look' for a game if you are just one guy. After I had all major graphic sets for the locations and most enemies, I started making levels and tinkered on the gameplay and decided on the fly what enemies I should add or what objects, power-ups or weapons I would need to make the game interesting.
When I started making the first real levels for the game, I had about 3 weapons (no alternate fire modes, those were the last I decided) and about 6 or 7 enemy types. The rest were improvised. When I ran around the marsh for example, I thought to myself "man, some green big zombies puking stuff at you would be cool here" and stuff like that

Alright, I'm talking way too much here I think. If you have any questions, feel free to ask
