You can LOAD a stage u died on openbor, the engine just auto save!
Difficult and other design decisions its up to the creator. One thing i will try to improve in my next mods is a best balance, but never easy!
Also: There's a lot of shooters made on openbor engine. And yes, u can do a mod the way u said (maybe already have some around...)
Also 2: Chainsaw is powerfull in really close range. The game had 2 sections of shotgun, i added some weapon variety on specific sections, and that's it! I never wanted Jennifer a heavy weapons game, i wanted to people use her own moves to make combos, extensions, etc...