So, since my last post about Unatyx, and the download I provided (which was game v0.001.03) I have updated it twice, however revision 04 didn't have a download as I was already working on 05, and if I released a download for every single version.. we'd be here a looong time.
Anyway, Unatyx v0.001.05 fixes a few bugs, including pathfinding (enemies now dynamically update their path, also taking into account towers placed after they spawned. This comes at a minor performance hit though, as rather than calculating the path before each enemy spawns, the enemies calculate the entire path every time they reach the center of a tile, to determine which tile to move to next.
Also note that trying to block an enemy as they're moving into a tile by placing a tower there may or may not crash. It will either stop you placing the tower, or simply crash. I 'll be fixing this in r06 if I can :P
Finally, I fixed the crash when you block the path to the exit entirely. Now, assuming you would be blocking the way of at least 1 enemy that has spawned, you won't be able to place the tower. However, if you block the path when all enemies are dead, new enemies that spawn will simply move diagonally through everything and off the screen (Don't ask o.o)
So yeah. Full changelogs and what-not can be found on the pixeljudge forums, as always (http://pixeljudge.com/en/forums/unatyx/). So, I'll be releasing a download for r05 on there soon.. maybe, or the download might wait until r06.. or r07.. or r389.. I dunno. When I have a version with more bugs fixed than added, I'll release a download.