Ok, Key Rushes; they’re good and all, and they’re a solid implementation in the game. But they’re way too rare. I was thinking of them appearing randomly like once every 10-50 missions flown in your inbox or the next planet you explore/a random UFO that spawns in a mission that when destroyed will open a portal/a random portal that will come near you every now and then that when interacted with will take you to a Key Rush mission.
And if you think this is too much, reduce the key amount from the usual 400-3000 to 200-1800.