Yeah, there were some really hard secrets in TR1. I remember that really hard to find secret was in Tomb of Qualopec behind the gold statue. In Colosseum there is also a quite hard to find secret, that which we need to stand on some tile and jump on platforms. There is also really hard secret in Palace Midas in gardens, I always had trouble to find the switch in bushes. And as you said the secrets in Cistern and in Tomb of Tihocan are hard to find. That's all secrets that are hard to find in TR1 in my opinion
