If you guys want to use a FAQ for anything (which I don't recommend unless you really want to know what something does) then there is either the
Wiki or
PlatinumGod which is my personal favourite, just because it is super easy to use and it has everything on one page with a search function and all.
@AnandI think I know exactly the item that might have caused the constant invulnerability haha. Also on PC you can restart whenever, but not on console I don't think.
One thing I still love about the game is picking up one item with another one and then finding out they synergise in a super cool way that you didn't expect at all. Some really good combos out there that can just transform your run.
@r_hjort@AnandThere are a few tells. Typically they are
surrounded by 3 other rooms with accessible doors, so this can narrow it down a fair bit. Plus
some rooms are just more likely to have a secret room attached. I have a pretty good feel for them by now and you will too the more you play. Its just one of those things you slowly start to figure out.
On the topic of Greed mode: I don't like it much either. I basically finish all the characters on it then never go back, and that is what most of the community is also like.
On the topic of Hard mode: Hard mode isn't that different. Different enemies and rooms can show up in, as well as less heart drops. But its not dramatically different. At launch (on PC) it wasn't fun though as all consumables had an incredibly rare drop rate so even going in an Item room was impossible on most floors. Thankfully they changed that.
@r_hjortSome of the challenges are harder than the main game so beware. Others however are super easy and just fun to do. They don't all unlock amazing things, but there are some useful things locked behind them.