Multiple Simultaneous Runs

[Polly Prissypants]

This one's directed at the devies, yes.

I'd be so good if you'd make it possible to have the option to run multiple runs at the same time.
I like to play very "seroiusly" and try hard, but I also like experimenting with different deck-builds, run-strategies and tactics, etc.
For the "serious" runs it's pretty clear and straight-forward - I strap in and commit, and this is perfectly fine.
For the other ones it's a whole range of different things, but I'd like a minut to write about the "commit" part of the previous sentense.
The commiting is the problem when it comes to experimentation - you don't want to commit to anything when experimenting, but you have to, making the experimentation a problem. Additionally, you can't choose the cards you get making experimentation more difficult...
I'm trailing off here...

My point is - I don't want to commit to every single run I go into.

Sometimes I want to see how far I can get and what I need to work on with a totally nieche deck-build. And, I want to do it now when inspiration struck... in the middle of a current serious run. Or I got tired, but want to continue playing Spire - if the option existed, I wouldn't risk the high-stackes end-of-the-game run I invested 1.5/2.5hrs. I'd save it and start another for-fun-only run... maybe that one turns into something huge for me.
If I had the option to save the current one and go into another one that ends in 15mins, I'm happy that I learned from whatever I was experimenting with and I saved the serious one for later.

Just make another menu screen beetwen the Main Menu and the actual run.

So, from the Main Menu, a player would go to a Current Runs screen.

There, you'd have a bunch (or, better, make it only 3 slots) of "save" slots each displaying the essentials (character being played for that run, current HP, relics, and maybe even you can have a Deck button that opens up a screen displaying what cards are in the deck of that run).
You click on whatever "save-file" you wish to play and - you continue playing that Run.

Then I can smoke a joint in the middle of a serious run, stop that one and start another.

[Polly Prissypants]

PS Your game's a beast; I've did about 16-18hrs in the first 24h of buying it.
That hadn't happened for me in a really long time.

I'd like to see you keep it up in a Binding of Isaac kind of fashion - tightening up the game-mechanics (and the code, of course) and adding, adding and adding new content and mechanics.

All the best, guys, and I wish you luck, most sincerely.