The first 2 youtube links is the first SR game. You can only use Tenma there.
There are choices to be made and you need to rotate the analog stick on the PS2 controller on some parts like swimming, chasing Hanai who has kidnapped Yakumo, the bike scene...etc.
It's more of the Tenma route where in if you fail certain objectives there is a different outcome. Much like the Harima matrix scene on SR s1 where in he grabs the arrow and confesses to Tenma! What?! lol
The 2nd youtube link is the horror house, that is where you get to chose the characters, but you need to unlock them first. Tenma and Harima are unlocked, then so on as you finish the game, this is the more off the Sim Date. Where Harima or a certain SR character gets his/her ending.