This time I focused on the “aim” part… adjusted range and accuracy to make each weapon more unique. There are also new crosshairs which resize based on the accuracy.

The one in the video is my current favorite but there are other options…

The alien AI was a mess. It tried too hard to be clever. The code was fragile and the behaviour unstable.

I threw it all out and implemented a simple flock / boid algorithm. The aliens will stick together and try to approach the player in natural looking groups.

A* pathfinding is gone too. Instead, the player character drops invisible scent markers with a limited lifetime. If aliens cannot get a clear line-of-sight to the player, they will look for the scent dots and follow them. That can eventually lead them back to the player, even around corners etc. It makes it look like the aliens know what they’re doing. Which, of course, they don’t.

The new tileset is coming together nicely. I made a “master sheet” with all the tiles to keep things organized.

I implemented a new material system for tiles. In addition to the visible texture, each tile had a lower resolution bitmap which defined the material at a given spot. This was used for special FX like bullet impacts that vary based on the ground material they hit.

I got rid of that and switched to a polygon based approach which plugs into Box2D. Material polygons are created as invisible objects in Blender and exported into the game.

I also changed the way fences are placed on the map. They are now baked into tiles, so map editing is much easier.

The metatile system is still in place but without the editor. I get enough variety from Blender & Pixelmator alone, so it wasn’t so useful. However I now use its multi-layer feature to draw the fences, because they need to have separate ground / shadow / foreground layers for proper z-ordering.