У вашего броузера проблема в совместимости с HTML5
Good part starts from @2:55 :)
If someone wants to test this himself, here's download link for my save file :
https://drive.google.com/open?id=1vl8BTHBimNtANmq0DrXH8pyS7QYKJW_9
Units used in assault (two main ones) :
Harbinger Gunship - 134
Apollo Fighter - 337
PC :
CPU : Core i7 4960X 4,5GHz
RAM : 16GB RAM 1600MHz (Quad Channel)
GPU : GTX 1080 FE (stock)
^Still.. not enough for fluid framerate.
Game engine isn't capable of handling the ammount of units on map (sadly it's DirectX 9 engine).
Copy it to game saves folder, and it should show up on "Load Game" list under "Campaigns".
PS. If it wasn't obvious, this was on Hard difficulty ;)