Either a tutorial, or better translation, and some tooltips.

I don't understand some of the items and stats:

what's "change gain", or "pain damage"?
or life recovery 5, is it 5 hp per second? 5 hp per minute?
or collection scope 100, is it 100 pixel radius? or is it a percentage?
and what happens if I buy more than 6 weapons?

I don't know how to play this game.