Thanks! I hadn't realized but Tierra and Avida are quite similar to SproutLife. I found this video that explains a bit about it https://www.youtube.com/watch?v=ouF8wKxXWFQ&t=1050s

I wonder if they also encountered the issue where the genomes/programs get simpler over time. In some ways one would expect evolution to increase complexity, but what I found happening is that prioritizing reproduction means creating pressure to decrease complexity, thereby increasing the reproduction rate and decreasing the footprint for negative mutations. The way SproutLife counteracted this was to add a "competitive" metric where bigger organism win over smaller ones, kind of like big trees casting shade to block smaller shrubs.