OP

Quoted from idealjoker:

UPDATE
I implemented the first two useful changes today:
I like the Fishbone-Us target code in the L2 ROM release much better than in the L5 release, because it is much more sensitive. The main reason for this is that in L2 the opto triggers both on closing and opening, while it only triggers once in L5. Additionally, L5 allows a maximum of 2 triggers per target hit. Since I'll base the home ROM on L5, I reverted the fish target handling to L2. (My eventual goal is to make the target gradually more difficult as you score points from it.) This was more tricky than expected. There are about 40 bytes of code in the L5 switch handler that deal with limiting the number of triggers per hit to not more than two. It's tempting to assume that it's this limit that makes the difference. However, that code never does anything on my machine. It would only come into action if you would get 5 triggers in the L2 code, which is not something that I think I have ever seen. What actually makes the difference is a single flag bit in the switch table, which makes the opto generate twice as many triggers in L2 than in L5.
I made a simple fix for the famous trashcan light bug. You can see the effect of the change twice in the video below, at 00:48 and 01:48. I'll most likely change the sound effect to the "What's all the racket" call-out. I think that I should also award the empty-trashcan score when it's unlit. The game does not feel right without the callout and I think that the score is appropriate, too.