Light Up the Night is one of the first card previews from the up coming Innistrad: Midnight Hunt. It’s a card that definitely harkens back to Fireball, Disintegrate, Kaervek’s Torch, Blaze and so on and so forth. There have been a lot of red X spells in the history of Magic, and this particular one has a lot going for it.
First of all, it has flashback. Now, it’s not as powerful, probably, as many flashback spells, given that you need to have a planeswalker or two in play to achieve maximum power and also you risk losing your planeswalker if your opponent is able to do something in response.
That being said, X spells are strong, and even without the flashback part of the card, this one is reasonably strong. It’s also important to note that occasionally you’re going to have to be willing to trade your planeswalker to kill a creature that may have just attacked your planeswalker anyway. All of this being said, I don’t think you necessarily even need to have many, or maybe any, planeswalkers in your deck for Light Up the Night to be a reasonable card.
Part of the upside here is that if you target a creature or planeswalker, Light Up the Night does X+1 damage instead of only X. This is very important as creatures in Magic nowadays tend to be a bit ahead of curve, or at worst have toughness equal to their mana cost. Previously, to use X spells to remove a creature like that would cost X+1 mana. Now, you’re only paying X-1 a lot of the time, and X+1 only when you’re removing particularly strong creatures.
Overall, this is a good card for aggressive red decks, capable of removing big blockers, but equally capable of providing a lot of reach, particularly in games that go very long, which can be a weakness of that kind of deck. Sometimes in this games, you’re able to trade one card for six, seven or more damage, which is somewhere a red deck wants to be.