Some instants and sorceries with delirium abilities have an upgraded effect when they resolve or a modified cost as they're cast if there are four or more card types among cards in your graveyard
The deck is packing some other useful tricks like winning on our upkeep instead of reanimating with Mortal Combat, generating tons of mana with Songs of the Damned, one-shotting opponents with a surprise Soulshriek, or giving all our reanimated creatures haste to immediately win with Crashing Drawbridge
Most others will be able to avoid over extending into it and have enough value effects that you are not getting much more than an even trade with your six mana spell
New additions from MH3 can potentially give them the power boost they need to compete again.
Foil $12 rather than its mana cost.) Whenever one or more creatures you control leave the battlefield without dying, you get an experience counter
First, consider a classic enters-the-battlefield trigger