Yes, it is repairable ... if you have the tools to do the job along with the expertise of working on damaged PCBs, but be prepared to buy a replacement ecu anyway.
The new diodes must be connected the correct way round (of course), as shown on the diagram or printed on the board and prior to the new components being fitted, all traces of carbon should be removed because of the possibility of shorts across the board between the pads.
You might also have to wire the new diodes back to the nearest clean solder pad rather than try to solder them to the damaged ones.
I have repaired boards in a worse condition than that, but back then I had all the proper kit for doing it.