I play gazlowe to lvl 10 and found I like this build. You can do anything except kill other hero so I don't recommend for who want to play this guy as assassin. This build for who want role like this. Solo to take mercenary camp or boss and be machine to get massive exp. Keep pusher. If this style is what you want, try it.

Tier 1 Regeneration Master with this you can be like tanker in late game. You can be a front line but don't expect this too much. In this tier you must keep lvl up from minion only. Help your friend sometimes if they are near but don't forget. Regeneration globes is your primary target.

Tier 2 Mercenary Lord This for you can go solo mercenaries and come back alive. After you upgrade this talent. I recommend you take Siege giants for speed kill minion and push.

Tier 3 First Aid This will help you in any case. It like you bought insurance and with this. You can solo boss when you got talent tier 4.

Tier 4 Robo-Goblin This is core talent that you must up. After you up this talent. Siege giants and Knights is piece of cake but for boss I recomment you go at lvl 11 or 12. If you idle, kill minions for Regeneration globe.

Tier 5 You can have Burning Rage or Sprint. It's up to you.

Tier 6 Stoneskin For your life and you can act as semi-tanker right now.

Tier 7 You can choose from Hardened Shield Fury of the Storm and Mecha-Lord. If you want to go help your team as front-line, Hardened Shield or Mecha-Lord is for you. If you want help your team as rear guard and increase pushing lane performance, Fury of the Storm is best.

I hope this guide can help you in some way.

PS. I write this guide for my friend.