Frontier Defense is so awesome! I was getting a bunch of XP. I got my Monarch from G3.17 to like G4.5 in one game! I'm thinking someone had one of the pilot weapon warpaints though. Plus you get your Titan really fast, so it's like total carnage. Also I barely noticed any difference with Power Shot after the Hidden Compartment nerf.
Scorch has three thermite rounds in FD, but they are Aegis Ranks. I've unlocked the first upgrade, which increases the capacity of the launcher to two rounds. Legion's Rank 20 upgrade is godly. ALL of his kits activate! Yes, that's right, you can have 140 rounds, 20 seconds of Smart Core, your Gun Shield blocking more damage, move faster with your cannon spun up, AND have two Power Shot charges at the same time! Monarch's got ranks that have her electric smoke generate shields to you and your teammates, have her start out with a random Core 1 ability (at Rank 20, you can seriously start out with either Missile Racks, Arc Rounds, or the one that allows you to give shields to teammates. Hopefully there won't be a chance of a duplicate. I wouldn't want to start with Arc Rounds when I already have that equipped, unless it bypasses charging up my first core and starts charging my second core). Papa Scorch has an upgrade that either allows you to have two firewalls or three traps for cooking that pizza faster. The Titan warpaint pack looks really good right now.
I saw that both warpaint packs were on sale (pilot pack was 37% off, making it around $16 and Titan pack was 28% off, making it $18) and the Angel City pack, Colony pack, and Monarch's Reign pack are all 35% off (they would be around $17 a piece). IDK when the sale ends though.