Hi,
Just some ideas.
In the first game I think the most important thing is how black did not put much pressure on white's invasion at

. Moves like

and

(

also in some way) look very gentle. After moves like

black should be able to torture white by keeping w's stones as insecure as possible. Moves like 79, 81 and 85 don't reduce w's eyespace. White was badly outnumbered in this area and still, he manages to live with more than 10 points, in sente and after having reduced black's territory to almost nothing.
To be a bit more precise:

probably better at s11 which 1) reduces w's eyespace 2) leaves a defect in w's shape at r12 3) encloses some points on the side for black

probably better at s9 which 1) reduces w's eyespace 2) encloses some points on the side for black
You generally don't have to kill invasions like 74 (well, sometimes you have to

) but black should use the fact that he has more stones in the area to keep w under pressure. The goal is (generally) not to kill but to gain points and/or strength elsewhere. In the game black seemed more concerned with the security of his stones, spending two moves to capture a white stone with 79 and 81, which gave white time to extand and live confortably. Black should not worry that much about his p11 stone because he has a lot of support in the area (n15, L10, k7, the p3 wall). Instead he should pressure w's eyespace and make territory above and below w's group.