I recommend you to go into the settings and turn on found hud(shows you all the items you got), the extra hud (on small)(shows stats) (might have mixed up the effects of the last two)and turn bullet visibility to high (makes you able to see enemy bullets slightly better)
Also red fire is angry fire and needs to be put out quickly or else it will start shooting at you whenever you’re in its direct line of sight. Purple fire (which comes later) has psychic properties and its shots will chase after you like little homing missiles which is very much not fun Also for the usable item the number of sections in the charge bar is how many rooms it takes to recharge the item. Every time you clear a room your item will gain a charge. If there’s only one bar then that means you can use it each and every room without worry, which is really good for items which repeatedly spawn those little blue friendly spiders or blue friendly flies as it enables you to build basically an army that will attack things for you The status effect each pill gives you shuffles every time you start a new run. So while in one run the completely yellow pill might have made your tears shoot faster that doesn’t mean next time you restart it’ll do the same thing, next time it might make you drop a dozen bombs all over the room (explosive diarrhea) or it might make you move slower and a different colored pill will be the one to make your tears shoot faster Cards however are consistent in their effects, ‘X - Wheel of Fortune’ will always spawn a slot machine when you use it no matter what run you’re currently on Speaking of slot machines, you can blow up slot machines and blood donation machines to potentially get loot if you don’t feel like playing them, I sometimes do that after I’ve gambled away all my coins on the slots. The blood donation machine usually drops hearts when you blow it up and each machine has a chance to drop an item that can do the task the machine it came from does
on the options you can active extra hud so yo can see your items and found hud to see the status of your character, azazel is one of the best characters to use on the start, hard mode is better because if you beat like mom's heart you will get a mark if you get in normal mode you will need to make the marks again in hard mode, the room that you spend the hearts to get items if you skip it you have a chance to get a angel room with found hud you can see the chance with both angel and devil deals, if you don't get damage on your red health you can have chance to get the deals so you can get damaged with blue and black hearts to not lose deal chance. edit: when you kill mom you can dowload mod on the steam workshop like external item descriptions is the one that show what the items do.
My man, I know you're trying to find out what the game can bring you, but there's a LOT of items, almost 2k if I'm not wrong, install the mod: Description Items mods. It would help you a lot to understand some items and trinkets, that made a lot of things (I been playing Isaac since 2014 and I still don't know what some trinkets do)
yo install external item descriptions thats the mod lazy mattman uses it tells you what cards, pills and items do also in setting you can turn on stats so you see your stats and btw tears up: you shoot faster range up:you soot further dmg up: you deal more dmg shot speed up: your tears fly faster hp up: is the heart container in the top left