You can only control firing by entering manual mode. You then have to look after the water and air supply as well. If you don't run the injectors in manual mode the boiler will run out of water. The automatic fireman is currently set up to maintain an ideal firemass which is either read from the eng file or determined by the other dimensions taken from the eng file. It also looks after the boiler water level, so if the other data in the eng file is correct, it will never ever give you a fusible plugs message until the tank or tender runs out.
If you download the document I referred to you will see what is needed to produce a reasonably accurate steam engine simulation. The eng file must have a reasonable boiler size for OR to run with. Unlike MSTS, if the engine is driven hard the boiler will run out of steam, and when pressure drops, so does train speed.
The problems with smoke are known and are being worked on, inverted level crossings is a new one to me.
Mouse controls are not implemented yet. I find zero problems using a keyboard and keeping to time. Perhaps you could expand on this aspect. We may already have the answer.
Beer is not a matter of life or death, it is much more serious than that.