I seem to have a problem with my latest HWA platformer game project. Basically, placing a layer, even just an empty one, below the current bottom-most layer, causes CPU usage to increase a ton every time there's just a few animated objects on screen in runtime. Normally when there's about five enemies on screen, my CPU usage stays below 10% at all times. With the additional layer, CPU usage maxes out and framerate starts going down. 10 enemies is unplayable, whereas I see no slowdown at all normally with 10 enemies.
This problem happens both in HWA build 249 and 251. I tried to test the game in non-HWA, but it crashes right from the start, so I dunno if it's a HWA-only issue.
The problem seems to be with the current bottom-most layer, which contains pretty much all the action, aside from HUD elements and such. Placing a layer above/below any other layer makes no difference to CPU usage. And like mentioned earlier, object animations seem to be the biggest factor. Lots of non-animated actives doesn't seem to be a problem, but 5+ makes the CPU burn.
So, I've tried slimming down things a bit, removed all other layers aside from the gameplay layer and a new empty layer below it. Deleted just about all extensions. What I have left, that are currently needed for the game to function without needing to change the code a lot; Named Variable Object, Array and three Active Pictures (level tilesets are loaded from these at frame start, then not used anymore).
On the coding side, there's a pretty basic custom platform movement going on, mostly non-fastlooped collision checks, value comparings, a detector for enemies and player, etc. I've never seen that stuff cause problems like this, so I don't see why they would here, especially with just an extra empty layer.
Blending types I've used include Additive, Simple Mask and XOR, though I think I've tried changing all those to None too.
I'm running out of ideas here. :/ What could be causing this? Any ideas?