Mana is one of the most limiting factors in Magic , so effectively doubling it is an incredibly powerful effect
You can flash it back in the same turn, but if mana is tight, feel free to flash it back on a different turn
Shuffle your hand, library, and graveyard together into a new library and draw a new hand of seven cards, leaving all cards in play where they are
Shift 5 seriously inhibits this cards ability to have an impact as by that part of the game you will already have likely been doing a lot of ramping
Green is a great color identity, so players don't have to be too picky when deciding on a background for him, and the deck's included background, Passionate Archaeologist, is probably the best choice
The spikes were 0/0 creatures that entered the battlefield with a number of +1/+1 counters that they could remove to activate abilities