Casual burn deck

I love a little red/blue burn action.

I know this is casual, but I see a few possible tweaks that could help the build out that you could implement cheaply.

Tzaangor Shaman is pretty slow and since it's useless on it's own (beyond being a 3/3 flyer), you could most likely get more value out of something faster/more reliable. Same problem with Rootha really. Even something as simple as Electrostatic Field would probably have a better impact, as it's cheaper, has no maintenance cost, and can double as a blocker to slow opponent down if needed. Personally, I'd think about Bonecrusher Giant // Stomp and/or Scalding Viper // Steam Clean in their place(s), as both are cheaper value engines that work on their own and that synergize with your tap damage fellas.

Some other cheap and high synergy cards to consider would be Needle Drop, Preordain, and Gitaxian Probe (though it's about 4 bucks), as they all draw you cards on the cheap (which helps you tactically tremendously as you get through your deck) while triggering your damage boy.

Divination is a little too slow and clunky without mana acceleration, even with two copies, as you're going to burn (ha) a turn using it and probably not be able to do very much for the rest of the turn, so you're giving opponent the tempo advantage while you take the material advantage, which is sort of the opposite of what burn does. Same problem with running 2 copies of Treasure Cruise (which works much better with fetch lands and high turnover builds that dump spells like crazy), so I'd generally recommend cutting Divination entirely and cutting down Treasure Cruise to 1 copy so you're basically guaranteed to only topdeck it while you have a full grave and can actually use it. You can actually duplicate the material gain aspect of these cards in a better way by running Hearth Elemental // Stoke Genius, which lets you burn through your hand then cast its draw ability without having to discard anything (netting you a +1 in material), then cast its critter half the same turn for cheap (probably only 1 red) or save it for later (netting you a +2 in material with a 4/5 beater).

Fiery Islet would also be perfect for your lands, as you're gunna be topdecking useless lands and running some Islets will help mitigate that while helping with your colors as well as not being too heavy a tax on you, as you can run the build on little mana if necessary.

Just some general thoughts.