Strange, repair looks fine, are you sure it was the cause of the crash? Repair may seem slow, especially with the damage boarding marines cause...
Weapons in inventory: It's missing tooltips, the larger weapons can only be carried in backpack (the very right slot)
Marine AI is beeing worked on, it;s not as easy, with special attack systems, special movement system....
Walls: true, but the actual problem lies elsewhere, marines shouldn't shoot through the walls. I will add some damage reduction
And again, thanks a lot for the test.