Choo Choo Engineers with gaming computers are not likely to notice any performance difference, but those of you with more typical computers will see some improvement in the performance of the game. I hadn't done a deep profile in a while so I ran it and found some inefficiencies that I could fix easily.
The largest unresolved inefficiency in the game at the moment are the scrolling damage numbers, so if you are playing on an older machine then do consider turning off the scrolling damage numbers from the game settings menu (cog icons on the left when in game) and you will see the game become a lot smoother. I hope in time to come up with a much better solution for scrolling damage numbers that is more performant.
As for the current easy fixes, I found that I was calling a GetLocalizedString method every frame in one of my scripts and that was quite expensive. That is fixed now. I also found that whenever a zombie or exp gem was activated for the first time it was retrieving some data from file which was completely unnecessary and is an expensive operation. I've changed it so that they now just retrieve the data they need from memory and it is much faster. I was also able to slightly improve my code that checks what zombies are closest to the train and remove some inefficiency in that.
Making the game more performant is important especially as I continue to add more content to the game. The more that gets added, then naturally the game can start to slow down if I don't revisit the code and figure out what can be improved. Damage text is at the top of the list for needing improvement and I hope in a future update I do successfully implement a new high performance damage scrolling text.
Keep on smashing the zombie horde Choo Choo Engineers!