Dead cells is the better game for me. I enjoyed Hades, but the layout/combat and platforming in DC just worked better for me.
It's the same type of game as Hades, in that every run you get a bit stronger. You kill enemies, they drop those glowing orbs (cells) and then you use them to unlock the weapons/powers and new abilities as you play. You then unlock new paths and all that. It has a ton more freedom with character builds, but as with all these vania/roguelites, you have to earn it the hard way
Starting tips would be learn the movement, especially getting used to the ground pound. Movement is just as key to getting through a level as fighting. Explore everywhere you can (other areas open up to you as you progress) and get the treasures. When you beat a level and get to spend cells, focus primarily on extra potions first and then go with starter weapons. Don't be scared to not use a shield, although there are so many and they are great in their own right (especially with parry) it pays tribute to Dark Souls by making sure as many of the weapons are as viable as possible. Those scrolls where you can pick a power up via different colours (green, purple and red), pay attention to the loadout you have/want and don't just necessarily spam the one that gives most health. There's tons more, but no need to overwhelm at first, and it becomes way more intuitive as you progress and it clocks.
Also the DLCs (both paid and free) and generally fantastic additions if you like the base game.