Alright! A big thanks for playing (again). :)
Good job on defeating the giant, I don't think that's easy! And that at the end is indeed a bug. But that was basically the end of the demo anyway, so you could say you beat it. :D
As to your technical questions:
- The trail behind the player character (and enemy projectiles and other stuff) is a dynamic triangle mesh that is constantly updated. I use a VBO and write to its float buffer on each render, updating position and color of each vertex. It's probably not the most efficient technique, but it works. :) I can share my (very crude) code if you're interested.
- Yes, that's a fragment shader effect that separates the color channels into red, green and blue and shifts them a bit based on some randomness and time. It also shifts every second pixel line to get that scanline effect. I use these effects very often in the game, for example when you get hit or things explode. Heck, the whole screen gets shifted more the faster you get :D
- I wrote my own level editor (which I already initially developed for my last game "Nubs Adventure" and upgraded for Rifter). I've already developed a few platformers and realized that it is crucial to have a quick iteration workflow between play-testing the game and changing stuff within the level as well as building it. That's why the level editor is right in the game, just hidden away with a config flag. If you're interested in the level file format, its plain text JSON files you can find in the game folder/archive (assets/maps/). The editor just parses these files, modifies them and writes them back to disk (I cache them in-game though).
- I'm using a few, some of which I bought. I think the one you mean is this one: http://signalnoise.bigcartel.com/product/neo-noire...
I'm happy to answer further question if you have any! :)