1. The only real problem with v1.30 is the vines in the Guy Tower and maybe the platforms in secret 3 (although I could be wrong there). I believe that in v1.25, the final phase of the Influka avoidance has stupid hitboxes on the knives (the glowy parts kill you). I'm not sure if that was patched in v1.30.
2. Saves can only be transferred to later versions of the game.
Sorry about the ambiguity of my answers. Hope this helps anyways.
Okay, just spent like an hour and a half on save 3 for secret 3. The platforms definitely behave differently than other games. Save 3 is really the only area that has trouble with that, though. I'm a bit worried about the vines in Guy Tower, though there don't seem to be that many precise vine jumps, so hopefully that won't be too bad. For Influka, I'm probably never gonna get past Boss Rush and if ever get close to beating any of the bosses, I'm pretty sure that I'll be able to replay the game up until boss rush, anyways. I would go and redo everything again now, but Secret 2 took me like 10 hours when I first played it and Shine and Bright was quite possibly the least fun boss I've ever had to grind out. At least there isn't as much wrong with it as I thought!
Thanks for the info!