Hi!
Well, creating the feature in Construct2 that will load custom levels into the game isn't the biggest problem, I did it for SUPERHOTline Miami.
The real difficulty is to create a decent custom level editor made specifically for SHOOTOUT Inc, I used Tiled Editor as a way to let players create their own levels and import them into SUPERHOTline Miami, it's a nice software, but users had to use specific settings and it was so easy to accidentally change something that would mess up the compatibility with the game, so it would be great if I could find a way to have a separate software made specifically for creating custom levels for SHOOTOUT Inc.
That's something I'm thinking about, but if I make something like this, that'll come after the release of the game. Thanks for offering your help on this, it's just that I can't answer now :-) And thanks for the love <3