Almost all of these problems have been encountered by other projects using the Unity engine, and the Mono-related ones have been encountered by projects using Mono. Why do you think Mono 2.8 has an experimental new garbage collector that's orders of magnitude better?
I'm guessing that it has something to do with the fact that AI war uses a HUGE number of small objects, rather than a medium number of small-medium sized objects like most other programs.
That is one of the challenges, yes, and we had to convert away from actually using their "GameObject" (I may have the name wrong) class for the actual sprite entities and drop down to a more primitive insert-point for their rendering pipeline (using DrawMesh now). That said, the performance is not
way worse than SlimDX, we're just dealing with a new engine after having worked out tons of efficiency tricks on SlimDX, so there's a learning curve we'll be climbing as we move forward.
Also, I hate to even think about this, but if these performance and API limitations won't be able to be fixed until the next major release of Unity, will you have to find and port to another engine again?
The problems are not nearly that bad.
Note that some of these issues are not small or ignorable; the stutter per 11 seconds
Are you still seeing the stutter per 11 seconds? We got the transient memory allocation
way down and it doesn't invoke the GC nearly as often.
and the crash on going to locked screen (64-bit only)
This is the biggest one left, and there are a few semi-solutions but basically yea, if you play on a 64-bit OS and play multiplayer the required functionality is not compatible with the ctrl+alt+del menu. Single-player does not
strictly require that the app run in the background (which is the problem we're having), though changing it just for that could lead to other problems. I have a couple other ideas that may be able to "fix" this by simply getting the cursor position an entirely different way, etc.
are both big enough to hold back a commercial release
The stutter would have been if we had not been able to do anything about it, but we have. And the ctrl+alt+del crash on 64-bit systems is not enough to hold back the release.
and the both seem to be fundamental problems with Unity and Mono 2.6, meaning you are stuck with them in this engine.
The GC thing is pretty fundamental, but it is workaround-able by simply making the game heap-static during most of the execution. That's not easy, and it's taken many hours to get where we are, but it is doable. The Ctrl+Alt+Del thing is not a fundamental problem with Unity in that all they have to do is make OnApplicationPause fire properly while Application.runInBackground == true, and we can simply stop checking for input while the app doesn't have focus and there will be no crashes. Whether they actually will fix that I do not know, but while I was initially very skeptical of using a 3rd party engine I have found that the folks at Unity conduct business with both integrity and competence.
In short, the situation is not so dire as you think
One lesson to learn in CS is that there is very nearly always a way to get around something, you just have to rethink the assumptions, requirements, and end-conditions, etc.
Edit: ninja'd by Chris, as usual
