[IIsi50MHz]

This reminds me of The Story of Mel[1]. It seems like you were doing Heavy Wizardry, which requires deep knowledge of technical details. The result can be Good Code in the sense that it makes the most use of available hardware and software resources, while possibly being hard or 'impossible' for people without equivalent knowledge to read or make changes. This is fine.

When you have more resources, you can write things prettier, not rely on side-effects, not 'abuse' features to do things normally considered BadTM, not "cross the streams". Or perhaps I should say when you fit easily within available resources, you have luxuries.

Don't feel bad about what you built, when you're aware of the constraints you were under and that the tradeoffs you were making were the best available choices at the time.

[1] http://www.catb.org/jargon/html/story-of-mel.html