Properly equipped Froggy G becomes a very mobile character. Your job is to finish off fleeing opponents, or swoop in to a fracas and turn the tide. In essence, you'll be your team's "Numbah 1 Stunnah." You'll be primarily focusing your Solar on Splash Dash with a secondary focus on Tornado.
Begin the game by taking Solar Bank, Splash Dash and Increased Speed. If you collected enough Solar during your drop, you should be able to run and dash through the free-floating Solar before the droids spawn to purchase Tornado. From here, the chase is on! Move back and forth between lanes looking for enemies weakened by your allies, and hit them with the one-two punch of Splash Dash and Tornado before they can flee. The stun of the dash not only allows you to get most damage out of your follow-up, but allows your allies either time to flee, or even better, contribute extra damage of their own.
As the game progresses, you'll want to take the shielding effect on Tornado as soon as possible, and then dump everything you can spare into Splash Dash's stun duration and cool down upgrades. Once those are taken care of, invest in health and the remaining Tornado upgrades. Your stun should be so high that Tornado Movement speed is not a concern. Instead focus on Increased Attack Speed and Twister Tweeters, allowing you an extra burst of damage to finish your combo. Properly timed, your Tornado should end right about the time that your dash is ready to go again, allowing you to stun them again for a few extra shots, or make a quick escape.
Later in the game, if you have managed upgrade both Splash Dash and Tornado, your twin-shielded attacks will allow you to perform hit-and-runs on turrets. The damage is not significant, but the alarm will often draw enemies for you to take down. Plus, every little bit helps. Increase your health if you enjoy this tactic, because the turret will inevitably get a couple of shots in.
Finally, with an emphasis on mobility, Froggy G can jungle very easily. His dash can kill entire groups of neutral enemies. However you may decide to take a Weapon Damage Increase to allow you to take them in two shots of your gun instead of three, just in case you miss with the dash.
Splash Dash: Stun Duration, Cool Down 1, Cool Down 2
Tornado: Attack Speed Increase, Shield, Twister Tweeters
Gun: Increased Damage (optional)
Standard Upgrades: Max Health (optional), Movement Speed, Piggy Bank
Clunk: The "Sapper" build compliments Froggy G. An enemy stunned by Splash Dash is easy pickings for the normally plodding tank. This duo is well suited for crowd combat.
Leon Chameleon: Working together, these two can quickly defeat any solo opponent. Travel together and rack up the kills.
Sheriff Lonestar: Be aware that most Lonestars are "Pushers" and are trying to keep enemies away, whereas you are trying to keep them close. Let him hold the lane, and pop in to finish off weakened enemies. Just make sure he doesn't push them away until you're done with them!
Voltar: Everyone's favorite squishy healer can benefit from your protection until he is leveled. You are mobile enough to be able to grab loose health or neutral foes to stay healed without his help, though.
Yuri: DPS-oriented Yuri builds are great friends to have. A few mines and laser blasts should cause your enemy to back off- dash after them and finish them off.