T-Rex was a part of exploration at least in original TR not that retarded anniversary edition. It was waiting there to scare the crap outta everyone. Original T-Rex still makes me nearly jump out of skin even though I played TR1 so many times. I usually don't kill him, it's amazing that 90% of bosses in TR1 were optional and you could just leave them alone. In TRA everything was forced. If that was true why there are so many crappy games that extremely popular?