On the Grave numbers, you also have to factor in $3 for killing Imp – so net I’ve really only invested $1 into Grave at that point.
Playing Imp P1T1 is generally regarded as a strong play, Just worth having in mind how it can go wrong sometimes. Its amazing how complicated even the first few turns can be in Codex!
Yes, I feel like I’ve lost it with a misplay very early on. A slightly different draw could have helped, but since we’re playing on forum I can sometimes really puzzle a turn and calculate different things I wouldn’t when I’m playing in person - here, by T4 I realized I was done for and considered (and laid out to see the results) of various different plays and none of them allowed me to maintain a position.
You have an interesting deck here. Sorry I couldn’t do more to test it.