Capcom clearly realised that DmC was gold and as such made a fair few titles that were either DmC cashins (hi Nightmare Before Christmas) or, like Chaos Legion, were games that tried to toy and play with the formula.

Chaos Legion had two things it attempted to bring to the table. One was instead of having lots of big flashy combos, you'd fight with summons instead. One of the Ps2 Castlevania games did this too and... kinda did it better. Chaos Legion's biggest problem is the speed of everything. Battles are often drawn out affairs where strategy and placement often take higher priority over spamming singular moves. This especially hurts during bigger boss moments and the rather linear arenas and locales don't help this much. It is still possible to mostly fight through without the use of summons but the limited moveset given really just enforces the idea of summoning and summoning often.

The other thing it brought was emo-grunge and lots of it. Guyliner, lots of pretty anime boys screaming into the void and questionable love-hate foe-yay rivalry/shipping akin to Sora/Riku Kingdom Hearts... But with much worse voice acting. Its annoying at times but its also hilarious in other moments.

That said, Capcom sure as hell made the game look damn good if anything. I do think that this game still has its moments too, battles, while slow, can often have some real chaotic moments hidden in them. But you do really have to look for them. This is very much one Capcom experiment that didn't quite work out.