So when you start making bigger games you realize all the things you did wrong in your smaller games... I've (successfully this time) added object pooling which will increase performance and reduce crashes. But mileage may vary between PC's.
Movement speed is finally fixed. The problem was not using a FixedUpdate with deltaTime, this was a simple error on my part for not understanding physics yet fully. Also camera flashing has been fixed on game start. And I removed the 300 fps frame rate limit.

Here's a short list:
1. Player movement no longer tied to FPS (higher fps was making the player slower!)
2. Object pooling added for all standard enemies, this should help performance
3. 300 fps limit removed when v-sync is off
4. Red flash is now enabled on game start, use pause menu > camera FX off to disable this setting