Infinite Evolution tips

How the game works, taken from its rules. Numbers are for World 1; later worlds have their own upgrade prices.

Orbs and spawners

The spawner makes a glowing orb on a timer. Tap the orb to release a creature.
The first spawner is free to claim and makes an orb every 7 seconds. Upgrades cut that to 6, 5, 4 and then 3 seconds, for 2, 4, 6 and 9 diamonds.
The Auto Popper pops orbs for you over time. The first one is free; after that each costs 1 diamond.
Better Creature gives orbs a chance to release a higher-level creature, and Double Creature a chance to release two.

Drag a creature onto an identical one and they merge into the next creature. Only identical creatures merge.
Merging always pays: the new creature makes more energy than the two it came from.
Each era has limited room. If a merge would send a creature into an era that is already full, it won't happen and you'll see "Too many creatures. Merge to make room." Merge the creatures already there first.
The Bio Magnet merges creatures for you automatically. The first one is free; faster magnets cost diamonds.
Use the transporter to move between eras.

Every creature makes energy every second, and the amount more than doubles with each level.
Tapping a creature gives a burst of about one second of its output. Keep tapping and the burst sometimes goes to 2x or 4x.
Tap the rocket or a tumbleweed when you see one: it pays 25 seconds of your best creature's energy at once.
The Creature Nursery sells creatures for energy, up to the best creature you have merged so far.
The Energy Multiplier doubles energy production for 15 minutes. The first one is free; after that it costs an ad or 3 diamonds.

Look in Research Upgrades for anything marked free or "Claim". When the game says "Claim your upgrades!", there is something free waiting.
Better Creature, Double Creature, Bonus Diamonds, More Sprites and Better Sprite Rewards each start with a free level. The levels after that cost energy, a little more each time, and the last level costs 5 diamonds.

Diamonds come from watching an optional ad (5 diamonds), from sprites, and from merges once you have the Bonus Diamonds upgrade, which gives each merge a chance to drop one.
Spend them on faster spawners, the Bio Magnet, the Energy Bank, the Energy Multiplier and the last level of each upgrade. Energy Bank upgrades cost only 1 diamond each.

Once you claim the Energy Bank (it's free and unlocks as you progress), your creatures keep making energy while the game is closed, up to the bank's limit.
The bank holds 1 hour of energy at first. Upgrades raise that to 2 hours and then 4 hours, for 1 diamond each.
When you come back, a dialog shows what your creatures collected. "Double Energy" adds the same amount again if you watch an ad.
An "Energy Bank is Full" notification means the bank has stopped filling, so open the game to collect.