TL;DR This game is okay but far from the best in the genre. I can't recommend it for the price when many other games of this style are better for less.

Friends talked me into getting this because they wanted to play it co-op with me. After playing for only about 4 hours I feel like I've seen all the content of the game already. Yes, I have more wizards to unlock and maybe some relics but each wizard doesn't really change up the game much beyond offering a different starting weapon and relics have a very small impact on runs.
That wouldn't be a problem if the game was so much fun I just wanted to keep playing it over and over regardless, but I've played quite a few garlic-likes and this one is only okay.
I think the biggest issue I have is with the level-up system, which is just far too bloated for how few levels you realistically get in a run. It encourages going all-in on one, maybe two spells out of the four you get, and the sheer difference in magnitude based on upgrade rarity makes builds heavily reliant on RNG. Again, you don't get that many levels in a run - you can expect to be somewhere around level 50-60 by the end of a run. That's not really enough for luck to just average out and means runs are very swingy based on the rarity of upgrades you get. This is also not helped by the fact that once you understand how important infusions are, you tend to not pick upgrades based on what they actually offer, but rather just based on which spell the upgrade is for. This makes level-up choices feel very one-dimensional as you simply pick whatever upgrade is available for the spell you want, or whatever the highest rarity upgrade is if you don't get one for the spell you want.
The elemental infusions are probably the best mechanic in the game and what makes this stand out compared to other garlic-likes. These actually tap into the excitement of mixing different effects and experimenting to try to make unique and interesting builds. Unfortunately in a full run you're only going to see 2-3 elemental infusion opportunities because of the issues with the level-up/spell upgrade system so in the end this provides just a blip of excitement in an otherwise pretty bland experience.
All this is to say that in the end, runs end up all feeling pretty samey. It doesn't scratch that itch of trying to combine different effects together to make unique and interesting builds because you're going to invest everything into one or two carry spells and only upgrade those if you can help it. The endless mode doesn't really help with this because the HP scaling on enemies makes them get insanely tanky even on endless level 2 and the exp curve rises so sharply that you're not really going to keep up.

協力プレイが断然面白い。時間によってはマッチけっこうします。
永久アプグレにキャラごとの性能アップとかが追� されたら面白くなる・・・かも？

good game, get it you wont be disappointed.