I don't help with code, but, i can help with concept. 1-Just add the button in editor level speed, or (and) lock fast forward button in editor. With 2 player mode,  -if you ready to lose 1 slot, and level factiacaly 1 player with 2 teams. In trap door and exit has new three configurations -Team one (green hair) Team 2 (blue hair) and All teams. And in gameplay new button. Change skills for team 1 and 2. In skills settings in editor 2 buttons. Team 1 skills and Team 2 skills.

To some extent you're right. I ready to help you. Many concepts, don't included in
engine. But, i create a new idea. A terraian, with break only choose skill. Example. Basher can't bash wall, with wall dig only digger.

Oh, forgot. This is a idea for mini fignting system. Hadouken for Lemmings 3, and Axer-permission skill. Every enemy, who is faces Axer, death. A two skills. Downer, -Builder, But ladder bulid down. Slider- (my concept) Lemming-aslo roller, but can slide for 3-heingt and stop slide when lemming get a wall.

I don't understand, how i make a engine. But, i ready to make CONCEPT in Asperite, and i don't have any idea for bombers. But non included skills for Lemmings 2, are included.

A small contest. I aslo starting working with interface of editor, (please, help me with engine)

Only 5 people. Contest theme- Mayhem levels gone Fun levels! Create a pack for Neolemmix with Mayhen levels, and recreate these level for Fun difficulty. Сondition- level possible for 100%.

Ok, i have a idea to 4 variantions of bombers. 1-Bomber for Lemmings 1. 2-Bomber for Lemmings 2. (no die lemming) 3-no time bomber, 4-3, but with knock back.

I have an idea to create a new engine for a Lemming clone. I would like to have a team for this. I will be the project leader and draw some sprites for the game. These include some lemming animations and a level editor concept. Then let's talk about something else.