So, this is a bunch of info that i tried to find via google/guides but NONE of them had/were of any help.

1. Playing endless mode on any difficulty will cause you to loose dots when you die (except on abyssal difficulty since there are no dots for that) BUT if you have already unlocked abyssal difficulty, and die on either abyssal difficulty or hard mode while in endless mode, you will NOT loose access to abyssal difficulty. But if your planning on going for the abyssal achieve and die while on abyssal mode in traditional story mode, it will take longer to get back due to the loss of dots from hard mode.

Also, i dont know if having fewer then 5 dots on hardmode and having access to abyssal difficulty would effect getting the achievement for abyssal difficulty in anyway since i have only just now started playing endless mode after having gotten the achievement for it.

In addition, you can still go back and play hardmode setting while having 1/2/3/4 dots in story mode and do a quick restart/go back to bar as well and it wont effect abyssal setting, it (abyssal difficulty) will still be there. However dying on hardmode or abyssal difficulty while in story mode will cause you to loose access to abyssal difficulty.

Lastly regarding this issue, you can play/beat hardmode and regain any dots lost from endless mode and it will not effect abyssal mode in any way (meaning if you lost hardmode dots on endless mode, you can put the game back on hardmode for story mode, beat it again to get back to 5 dots, and it wont effect abyssal mode in any way, you will still have it, so that way when your ready to go for abyssal achieve, and you end up dying on abyssal mode, your dots will be at 5 dots or whatever you got them up to prior to abyssal mode and you wont have to regain multiple dots.

2. There are NO secret rooms in endless mode, so if you were hoping to find an ease way to getting the secret room achievement, im afraid your gonna have to do it via the normal game, so go ahead and just use your bombs on those rock chests! (slim chance i could be wrong, granted this was after having gone through 20 lvls of endless mode using grenades on the one empty spot that the secret room would have been, so i doubt it).

3. You can enter the endless mode with one of the items you can buy with your faith points at the ancient statue that lets you. So go ahead and pick what ever item works for you! (i am a big fan of the atlantis bauble myself since being able to destroy enemy bullets will 100% make your run go smoother/longer)

4. Endless mode is just 2-3 rooms (might be 4, i didint encounter ones with 4 on my first run through) with a random portal stone room in the middle that you start out in. The rooms can be any type of room from (except bosses, those spawn after a set amount of floors have been cleared, and will only spawn 1 per every so many floors, you will still start out with the general boss's like in the normal game before getting the big boys to give you time to gear up).

So you might get enemy rooms, store rooms, game rooms ect.

5. You will encounter enemies with a multi colored outline and a name of some kind, that means they will have some kind of special power or ability that will trigger on death. So becareful when you kill them. No joke, my first special enemy was named honorable d (the d word relating to what men have for a reproductive organ, no joke, was funny to see the devs have a sense of humor, so be prepared for such things lol) and he made a big cross shaped explosion when he died.

6. Every floor will have at least 1 relic/item/gun drop of some kind. It will be like boss drops where it will change between 3-5 or so different items and you will have to time it just right to get the item you want. It will drop after all rooms have been cleared.

7. The portal to the next floor can open up from any of the 3-4 rooms, so becareful when it opens up, because it might open up after you have cleared only 2 of the rooms and you might miss out on the item drop for the floor if you go through the portal before your done clearing!

8. The free blessing statue also works for endless mode, so go ahead, set story mode to ease, commit seppuku 3 times on ease mode for a free blessing before entering endless mode.

9. Just like in the normal game, the layout and drops of the level will for the most part remain the same when resetted when you go back to the main menu and reload, so if you got a drop you didint want or missed the item/buff you wanted, you can just simply return to main menu, reload and try again.

10. If using the free blessing statue for your run, try to get the shopping spree blessing. It will give you lip stick and black friday allowing you to really stock up on relics during your run. Its also a good idea to skip/turn off most (except for zen) mini games that cost coins if your going to do this method, since saving your coins for the shop will yield more relics as a whole most likely for when a shop comes along (and saves you valuable shields/hearts as well from machine explosions and saving them for zen). Plus you never know when you will need some extra hearts/shields from the store.

11. Most likely my final tip since ive moved this game into my "beaten/finished" game tab (this tip applies mainly to abyssal difficulty since bosses just get melted on easier difficulties and dodging isint a big thing with a big powerful upgraded gun).

Be careful when using bullet based guns (famine especially) as you get higher if your pc isint a newer model. The further you get, the crazier your gun will get. And with bullets, not only will it get harder to see enemy projectiles, but there's a good chance it will lag your pc pretty heavily depending on its age/stats (obviously if you got a newer model/pc of the gods then chances are you dont have to worry)

Even more so on abyssal difficulty, since bosses get insanely tanky, even if your packing alot of power. So it might be wise to stick to laser based weapons.

My multicore pc dropped down to 2 fps using famine on prometheus on 4-10 on endless, and i RARELY ever get fps drops on indy games with lots of bullets but it was just too much, he was VERY tanky, i lagged out, and his attacks hit for about 2-3.5 hearts/shields a hit on abyssal at that lvl and i got ded.

Had a couple of the extra bullet relics like samurai soul, night vision ect, add in pierce, max gun lvl, more bullet upgrades, and many other synergies/pets ect that increase bullets shot, more then what i ever could have gotten/ever had period via story mode and yeah, famine, my fav gun, got me dead since the bullets just kept stacking and took so long to disappear lol, couldint dodge/move properly at 2 fps. He was too tanky at that lvl on abyssal to melt, got him to half hp in his first form/first hp bar before death. Just to give you an idea of what can happen.

Thats pretty much it, oh and this isint a true endless mode, its just "beat every version of the bosses that exist except for the general's" mode. If anyone has any other good info to add, feel free to add it in the comments section.