Do Point gain increase based on level?

nope
gaining points is based on how many GAs are created. Hence, points tend to increase rapidly on Tuesday afternoons when the latest humble bundle causes a spike. Being a higher level does not affect the rate at which points increase, it only grants access to level-restricted GAs

No

Nah, same for every level

FAQ says:

How do I receive or earn more points (P)?

All users on the site are given an equal number of points, and you cannot do anything outside of waiting patiently to increase your number of points. The number of points being distributed to users is based on the number of giveaways being posted to the site, and you'll frequently see your points automatically rise throughout the day.