This looks pretty nifty already! Needed to mess with the OpenGL version a bit ("export MESA_GL_VERSION_OVERRIDE=4.1COMPAT" did the trick), and it's running very smoothly for me
The most obvious thing I already noticed during the video is that the builder bricks are only 4 px wide rather than 6 px; maybe fixing this would also fix the issue with the gap? Related to the builder, L2 has a funny behavior where the brick of left-facing builders is placed differently from right-facing builders: For example, at a cliff edge, in one direction you can place the first brick so it protrudes 5 px, but in the other direction only 4. The collision detection of builders with terrain feels a bit too strict as well, but I can't say for sure.
A couple of other things you might already be aware of:
- You can't assign skills to lemmings that are currently performing a task.
- A few visual things: the animation of the floater is a bit funky. Also, permanent skills (floater, climber) invert the color of the lemming (green <-> blue) in the original game.
The Return key currently not mapped to fast-forward is very noticeable to me because I use it excessively in the original game, haha.
It's great how everything is extracted from the original game, no assets you need to include with the code, and any kind of modification to the game assets itself (I guess currently that's limited to levels) are automatically supported