Not romhacking related, but "retrogame" related...
I do not know if anyone here ever seen or used it, but I am finishing my second game using the "Arcade Game Studio" (ARGS), Bruno R. Marcos. The program is free, and more than a game engine it is a solution to make arcade style Ghouls and Ghosts, Bomberman, Commando, Horizontal or Vertical Shooters, without knowing a line of programming.http://www.bruneras.com/arcadegamestudio/index.php
Not the most versatile of all programs, and it serves more to certain specific types of games, however, you see the results coming very fast. View results with little production time is something important for an amateur who has little time available.
Another thing that helps a lot is how to mount the stages. The assembly of tiles is simple and direct: you selects the tiles (16X16) on the tileset and past it on the stage. Then, you click and add 8X8 markers to define what is solid, platform, spikes, ladder, etc ... In the end, you have the option to plan the scenario (like in a normal production), or create the level design in real time by setting the trial and error (or at least, use this method to test).
The program came to light in 2012, so I wonder why so few games have been produced by this program... this is why I'm making an "advertising" of the program here. Speaking of advertising, I'm almost finishing my second game:http://gamejolt.com/games/marlow-in-apocalyptic-acid-world-wip/91292
Soon, when the game is finalized, I will release the "source code" (actually the game's project files in ARGS) for those who want to use to learn how to work in the program, or use graphics and sounds I've created in your ow projects.