Just an updated list that I played to rank 40 this season after messing with new cards. I cut out all of the fluff and this is how it looks now.

RG Energy

Creature(20)
2 x Greenbelt Rampager
3 x Longtusk Cub
4 x Sage of Shaila's Claim
3 x Voltaic Brawler
2 x Electrostatic Pummeler
2 x Pia Nalaar
2 x Lathnu Hellion
2 x Bristling Hydra

Instant(14)
4 x Built to Smash
3 x Blossoming Defense
3 x Harnessed Lightning
4 x Highspire Infusion

Sorcery(4)
4 x Larger Than Life

Land(22)
2 x Cinder Glade
7 x Mountain
8 x Forest
2 x Rootbound Crag
3 x Aether Hub

What about Fling? Maybe over some or all of Infusion? Convert EOT dying Hellions into profit, and big damage payoffs in Cubs/Pummelers. That way you don't have to worry about removal spells when trying to Larger Than Life trample through.

The list looks good, fast and to the point. It also has 0 Amonkhet cards, which is something I'm starting to notice, Amonkhet goodstuff isn't good enough compared to our older goodstuff.
Still, you could safely add Samut as a curve topper because he/she's a powerhouse.
I would maybe run slightly less pumps, because drawing only combat tricks and no creatures isn't fun.

t2 removal t3 removal gg

Fling is a good consideration and it sounds like it could be a fun way to end the game without trample.


Sarcasm or stupidity?

Even just to give reach - trample in with a pumped Cub/Pummeler and then Fling it for the remaining damage needed. Plus, similar to Blossoming Defense, it gives you a response to removal - just converting it into damage rather than keeping it on board.

WW was prob being serious, viewing it in a worst case scenario light. But someone won (iirc, was runner up if not winner) of one of our tournaments with a Gruul energy list not too different from yours. No pummeler, but similar heavy non-creature spell count. I built it to try after seeing it do well in the tourney - had the occasional game where I'd not draw enough creatures and timely removal from opp would ruin it, but it was still a good list all in all.

Just was thinking 20 creatures you get approx 3 of them by first 3 turns without more filtering like copter motorist or titans strength. (60 cards deck : 10 first cards = 1/6 of deck. 20/6=3.)
If Two of them removed, all you have is pump and lands. Then you will draw a creature every 3 turns which is obviously gg...Not mentioning out of the 20, sage of shaila are not prime beaters on their own. They dont demand immediate removal.. they may hit once or twice with even pump but I think deck would need some serious reach... hellions are good for this. Other haste would help and Maybe some burn face... I didn't say for sure fling face is good option because it's also creature dependent.. they give creature pseudo haste though.

I made almost the same deck on my own and now saw this thread! Fling is better than built to smash. Invigorated rampage is better than both of them. I also used glorybringer at the top end as the flying and haste seem relevant. Pia Nalaar doesn't feel like she fits this dexk but I haven't tried her in it either.

I made this deck when pummeler was added to duels, so i've been playing and tuning it for a while. Fling is not better than built to smash because it doesn't add stats to your creatures, it just serves a completely different purpose.

Pia Nalaar is the next best 3 drop for us to be playing because it makes two bodies which are good for the whole pump spell game plan. Also her first ability has synergy with pummeler while the second ability can be used to prevent a block when needed. Glorybringer is a great card and definitely something to consider, but I want to keep this deck relatively fast with a lower land count so adding two five drops just isn't the move.